工学修士, 電気通信大学

博士(工学), 電気通信大学

Heterogeneous Integration

epitaxial growth

rare-earth

diamond

furactal

silicon photonics

エピタキシャル成長

希土類

ダイヤモンド

フラクタル

シリコンフォトニクス

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Electronic devices and equipment

01 Apr. 2016
電気通信大学 大学院, 情報理工学研究科 基盤理工学専攻, 教授

01 Mar. 2013 - 31 Mar. 2016
電気通信大学 大学院, 情報理工学研究科 先進理工学専攻, 教授

Apr. 2007 - Feb. 2013
電気通信大学 大学院, 情報理工学研究科 先進理工学専攻, 准教授

Feb. 2004 - Mar. 2007
電気通信大学, 電気通信学部 電子工学科, 助教授

Apr. 1997 - Jan. 2004
電気通信大学, 電気通信学部 電子工学科, 助手

Sep. 2000 - May 2001
FOM Institute for atomic and molecular physica, Guest researcher

Apr. 1992 - Sep. 1999
理化学研究所フロンティア研究システム, ナノ電子材料研究チーム, 研究員

Apr. 1987 - May 1988
日本電気㈱, 化合物デバイス事業部光半導体部, 勤務

Mar. 1992
The University of Electro-Communications, Graduate School, Division of Electro Communications, 電子工学専攻

Mar. 1987
The University of Electro-Communications, Graduate School, Division of Electro Communications, 応用電子工学専攻

Mar. 1985
The University of Electro-Communications, Faculty of Electro Communications, 応用電子工学科

01 Apr. 1977 - 25 Mar. 1980
埼玉県立大宮高等学校, Japan

Jun. 2019 - Present
委員, 電子情報通信学会 光集積及びシリコンフォトニクス特別研究専門委員会, Society

Aug. 2014 - Present
委員, 電子情報通信学会 システムナノ技術に関する特別研究専門委員会, Society

Present
論文委員, 電子材料シンポジウム, Society

Jun. 2019 - Jun. 2021
委員長, 電子情報通信学会 光集積及びシリコンフォトニクス特別研究専門委員会, Society

01 Sep. 2018 - 31 May 2019
委員長, 電子情報通信学会 シリコンフォトニクス特別研究専門委員会, Society

01 Jun. 2018 - 31 Mar. 2019
学術委員, ニューダイヤモンドフォーラム, Society

01 Aug. 2016 - 31 Jul. 2018
委員長, 電子情報通信学会 システムナノ技術に関する時限研究専門委員会, Society

01 Aug. 2014
副委員長, 電子情報通信学会 システムナノ技術に関する時限研究専門委員会, Society

01 Aug. 2012
幹事, 電子情報通信学会 次世代ナノ技術に関する時限研究専門委員会, Society

2002 - 2005
プログラム編集委員, 応用物理学会, Society

Si プラットフォーム上ダイヤモンドデバイス集積の実現に向けて
一色 秀夫
Lead, 日本信頼性学会誌「信頼性」, 46, 2, 49-54, Mar. 2024, Peer-reviwed, Invited
Scientific journal, Japanese

A significant increase in carrier concentration in TiO₂ by Sm doping
Asuka Ishizawa; Hiroaki Aizawa; Hideo Isshiki; Shinichiro Kaku; Kazuto Miyano; Xinwei Zhao; Mariko Murayama
Japanese Journal of Applied Physics, IOP Publishing, 63, 3, 03SP79-03SP79, 01 Mar. 2024, Peer-reviwed, Abstract

Sm-doped TiO₂ thin films were synthesized by pulsed laser deposition. The luminescence and donor-generation properties of thin films annealed at various temperatures were investigated. The results showed that Sm-related emissions occurred in the temperature range 500 °C–800 °C. The donor densities in this temperature range were two orders of magnitude higher than that of the undoped TiO₂ thin film. The effect of annealing within the temperature window indicates a local fine structural transition of the ligands around Sm³⁺ ions from T_d symmetry to the lower C_4v one; these ions are effective luminescence centers in TiO₂:Sm thin films. This local structural distortion also increases defect generation, and this increases the donor density in the same temperature region.
Scientific journal, English

Growth of CuAlO₂ on SiO₂ under a layer-by-layer approach conducted by digitally processed DC sputtering and its transistor characteristics
Mehdi Ali; Daiki Yamashita; Hideo Isshiki
Last, Japanese Journal of Applied Physics, IOP Publishing, 63, 3, 035502-035502, 01 Mar. 2024, Peer-reviwed, Abstract

A CuAlO₂ (CAO) bottom gate top contact p-type thin film transistor (TFT) is demonstrated. The CAO thin film is synthesized through a digitally processed DC sputtering (DPDS) technique, employing a precise layer-by-layer (LBL) deposition strategy. X-ray diffraction analysis exhibited distinct peaks beyond 600 °C. The CAO film shows a dominant phase along the (004) plane at the elevated temperature of 990 °C. The fabricated CAO p-TFT exhibits field effect mobility of 4.1 cm² V⁻¹ s⁻¹. In addition, the p-TFT characteristics were observed even in the as-deposited CAO film. The DPDS-assisted LBL approach offers a promising pathway for controlled stacking deposition routes in the growth of CAO thin films, enabling enhanced performance and device integration.
Scientific journal, English

The Role of Reactive Gas Pulsing Synchronized with Digitally Processed DC Sputtering
Hideo ISSHIKI; Ghent NAKAMURA; Yasuhito TANAKA; Shinichiro SAISHO
Lead, Vacuum and Surface Science, Surface Science Society Japan, 66, 8, 484-489, 10 Aug. 2023, Peer-reviwed
Scientific journal, Japanese

Atomically Precise Deposition of (Er0.1Y0.9)2SiO5 Combined with Digitally Processed DC Sputtering and Non-Radical Oxidation
Ghent Nakamura; Hideo Isshiki
Journal of Vacuum Science & Technology A, American Institute of Physics, 40, 5, 053406-1-053406-6, 01 Sep. 2022, Peer-reviwed
Scientific journal, English

Highly Precise Multi-Cathode Pulsed-DC Sputtering Employing Digital Processing -Application to Layer-by-Layer Synthesis of Cubic (Er0.1Y0.9)2Zr2O7 Thin Film-
Hideo Isshiki; Yasuhito Tanaka; Kodai Miyagi; Tomoki Kasumi; Ghent Nakamura; Shinichiro Saisho
Japanese Journal of Applied Physics, The Japan Society of Applied Physics, 61, SA1001, 1-6, 15 Dec. 2021, Peer-reviwed
Scientific journal, English

Development of digitally processed DC reactive sputtering and its application to the synthesis of (Er0.1Y0.9)2SiO5 layered crystalline thin film
Hideo Isshiki; Yasuhito Tanaka; Tomoki Kasumi; Ghent Nakamura; Shinichiro Saisho
J. Appl. Phys., AIP Publishing, 130, 185301, 08 Nov. 2021, Peer-reviwed, We have developed a digitally processed DC reactive sputtering (DPDRS) system that enables synthesis of arbitrarily designed atomically
precise deposition of metal oxide compounds. Pulsed-DC sputtering employing a digital pulse pattern generator can perform the temporally
alternating process of multiple metal sputtering and oxidation. High-speed switching of the pulsed-DC sputtering process driven by the
digital signal processing was confirmed from time-resolved plasma emission spectroscopy. Metal sputtering, which was temporally separated
from the oxidation process, resulted in a deposition rate higher than 1 μm/h. The DPDRS was applied to layer-by-layer synthesis of
(Er0.1Y0.9)2SiO5 (EYSO) films oriented to the ⟨100⟩ direction.
X-ray diffraction measurements indicated a formation of ⟨100⟩ highly oriented (Er0.1Y0.9)2SiO5 crystalline thin films. Photoluminescence
spectra and the decay characteristics also showed synthesis of high crystalline quality EYSO films better than those obtained by pulsed laser
deposition.
Scientific journal, English

希土類複合酸化物結晶と光集積化デバイスへの応用
一色秀夫
光学, 日本光学会, 50, 10, 406-411, 10 Oct. 2021, Invited
Scientific journal, Japanese

Rare earth silicates as gain media for silicon photonics [Invited]
Hideo Isshiki; Fangli Jing; Takuya Sato; Takayuki Nakajima; Tadamasa Kimura
PHOTONICS RESEARCH, OPTICAL SOC AMER, 2, 3, A45-A55, Jun. 2014, Peer-reviwed, Invited, ErxY2-xSiO5 and ErxYbyY2-x-ySiO5 crystalline thin films were investigated to apply to the high-gain media for silicon photonics. In addition to the sol-gel method, the directed self-assembly approach, using layer-by-layer deposition techniques, was also introduced to improve the crystallinity. The relaxation processes in Er ions were discussed to clarify the contribution of the energy transfer and cooperative upconversion. After optimization of the Er content, a Si photonic crystal slot ErxY2-xSiO5 waveguide amplifier was fabricated, and a 30 dB/cm modal gain was demonstrated. This achievement demonstrates the potential for compact and high optical gain devices on Si chips. (C) 2014 Chinese Laser Press
Scientific journal, English

Sharp and intense emission of Si-vacancy luminescent center in diamond film grown on Si (100) substrate
Hideo Isshiki; Kazuki Komiya; Kohei Kojima; Yuji Souma; Tetsuya Shigeeda
2014 IEEE 11TH INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS (GFP), IEEE, 2014, Peer-reviwed, Sharp and intense emission from the Si-V luminescent center in diamond grown on Si is observed. Possibility of the Si-V luminescence center as a light source for integrated quantum photonics on Si chip is suggested.
International conference proceedings, English

Role of Energy Migration in Nonradiative Relaxation Processes in ErxY2-xSiO5 Crystalline Thin Films
Takayuki Nakajima; Yasuhito Tanaka; Tadamasa Kimura; Hideo Isshiki
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 52, 8, 082601, Aug. 2013, Peer-reviwed, ErxY2-xSiO5 crystals have been proposed for compact waveguide amplifiers in Si photonics. However, the crystalline materials show quenching behavior with increasing Er concentration. We have investigated the nonradiative relaxation processes in ErxY2-xSiO5 crystallites and discussed the contribution of energy migration in ErxY2-xSiO5 crystallites. It has been found that the quenching behavior is governed by the diffusion-limited relaxation in ErxY2-xSiO5 grains, where, as we have proposed, the grain boundaries act as quenching centers. The experimental results were shown to be consistent with the diffusion-limited relaxation model. Using the proposed model, the energy transfer constant between Er ions C and the critical transfer length R-0 were estimated. The values are in good agreement with the values reported previously. (C) 2013 The Japan Society of Applied Physics
Scientific journal, English

Luminescence of ErxY2-xSiO5 in Si Slot Waveguide Structures
Y. Terada; S. Ban; Z. I. Bin Zulkefli; T. Nakajima; T. Kimura; H. Isshiki
2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR), IEEE, 2013, Peer-reviwed, Strong optical confinement to the low-index slot, such as ErxY2-xSiO5, is expected for TM mode in Si slot waveguide. The confinement effect causes the optical mode density modification, resulting in the enhancement of radiative transition. We have fabricated slab Si-slot waveguides with Er2SiO5 slot layers in order to demonstrate the dependence of radiative emission on the guided waveguide modes. The PL fine structure particular to Er2SiO5 crystal has been observed through the waveguide structure. We confirmed the enhancement of the TM mode edge emission.
International conference proceedings, English

Enhancement of Diamond Nucleation by Atomic Silicon Microaddition
Hideo Isshiki; Mikio Yoshida; Ryutaro Tobita; Tetsuya Shigeeda; Motoi Kinoshita; Kenshiro Matsushima; Takashi Tamura
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 51, 9, 090108, Sep. 2012, Peer-reviwed, The enhancement of diamond nucleation by atomic silicon microaddition is demonstrated. From the observation by surface-enhanced Raman scattering (SERS), the mechanism of bias-enhanced nucleation (BEN) with atomic silicon microaddition is discussed. We propose two nucleation processes, namely, i) generation in condensed amorphous carbon (a-C) and ii) carbon cohesion with the adsorbed silicon atom as the core. It is shown that the nucleation process ii) induces highly oriented diamond growth on Si substrates. (C) 2012 The Japan Society of Applied Physics
Scientific journal, English

Emission and optical properties of Si slot ErxY2-xSiO5 waveguides
Hideo Isshiki; Zul Izwan Bin Zulkefli; Takayuki Nakajima; Takuya Sato; Tadamasa Kimura
NANOPHOTONICS AND MICRO/NANO OPTICS, SPIE-INT SOC OPTICAL ENGINEERING, 8564, 2012, Peer-reviwed, Strong optical confinement to the low-index slot, such as ErxY2-xSiO5, is expected for guided TM mode. The confinement effect leads to modification of the optical mode density, resulting in the enhancement of radiative transition. We have fabricated slab Si-slot waveguides with Er2SiO5 slot layers in order to demonstrate the dependence of radiative emission on the guided waveguide modes. The PL fine structure particular to Er2SiO5 crystal has been observed through the waveguide structure. We confirmed the enhancement of the TM mode edge emission, and the intensity was about two times higher than that of TE mode.
International conference proceedings, English

Observation of 30dB/cm gain in Si photonic crystal slot Er xY2-xSiO5 waveguide
T. Sato; T. Nakajima; T. Kimura; H. Isshiki
IEEE International Conference on Group IV Photonics GFP, http://ieeexplore.ieee.org/sta, 2011, Peer-reviwed, ErxY2-xSiO5 waveguide slotted into Si photonic crystal was demonstrated. Strong optical confinement for the C-band is confirmed in this device. Optical gain of 30dB/cm was observed by VSL method. © 2011 IEEE.
International conference proceedings, English

Photoluminescence enhancement and high gain amplification of ErxY2-xSiO5 waveguide
X. J. Wang; G. Yuan; H. Isshiki; T. Kimura; Z. Zhou
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 108, 1, 013506, Jul. 2010, Peer-reviwed, ErxY2-xSiO5 (x=0-2) films have been fabricated on Si(100) substrates by the sol-gel method. Enhanced Er3+ photoluminescence of around 30 times for the ErxY2-xSiO5 (x=0.1) film was observed compared with pure Er2SiO5 film at the wavelength pump of 654 nm. Reduced upconversion effect and decreased nonradiative transient rate are two main reasons for the enhanced Er3+ luminescence in the new film of ErxY2-xSiO5. Above 10 dB optical gain can be achieved at the 1 mm length ErxY2-xSiO5 (x=0.1) waveguide under 30 mW pumping power, indicating it is sought candidate material for compact waveguide amplifiers and emitters in silicon photonics integration. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3446822]
Scientific journal, English

Highly oriented ErxY2-xSiO5 crystalline thin films fabricated by pulsed laser deposition
H. Isshiki; Y. Tanaka; K. Iwatani; T. Nakajima; T. Kimura
2010 7TH IEEE INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS (GFP), IEEE, 311-313, 2010, Peer-reviwed, We propose layer-by-layer deposition approach to fabricate ErxY2-xSiO5 crystalline thin films. Highly oriented ErxY2-xSiO5 thin films with high crystallinity have been obtained by rapid thermal annealing (RTA) crystallization following pulsed-laser deposition (PLD).
International conference proceedings, English

Phase separation growth of Er2SiO5 thin film in Si-rich ErSiO preform
H.Isshiki; M.Ohe; T. Samejima; T.Ushiyama; T.Kimura
Physica E, 41, 1055-1058, Mar. 2009, Peer-reviwed
Scientific journal, English

Formation of highly-ordered layer-structured Er2SiO5 films by pulsed laser deposition
Tadamasa Kimura; Yasuhito Tanaka; Hiroshi Ueda; Hideo Isshiki
Physica E, 41, 1063-1066, Mar. 2009, Peer-reviwed
Scientific journal, English

Luminescence properties of Erxy2-xSiO5 thin film prepared by sol-gel method
T. Nakajima; X. J. Wang; T. Kimura; H. Isshiki
IEEE International Conference on Group IV Photonics GFP, 134-136, 2009, Peer-reviwed, ErxY2-xSiO5 (x=0.1∼2) crystalline thin films with the same structure of Er2SiO5 crystal, are demonstrated. ErxY2-xSiO5 films with various x values were prepared by the sol-gel method. ErxY 2-xSiO5 films show a highly-ordered crystalline structure still for x∼0.1. With, decreasing the Er content, the photoluminescence intensity was almost constant till x∼0.5, and then increased strongly for x below 0.5. The PL decay time also strongly depends on x value. With decreasing x, the decay time becomes longer and becomes 500us at x=0.1, The decay time quenching is in agreement with PL efficiency. Here we discuss the decay time quenching in ErxY2-xSiO5 crystalline system. © 2009 IEEE.
International conference proceedings, English

Fabrication and Evaluation of Self-Organized Er(2)SiO(5) Crystalline Films for the 1.5 mu m Emitters and Amplifiers in Silicon Photonics
Tadamasa Kimura; Hideo Isshiki
RARE-EARTH DOPING OF ADVANCED MATERIALS FOR PHOTONIC APPLICATIONS, MATERIALS RESEARCH SOCIETY, 1111, 117-128, 2009, Peer-reviwed, We have developed self-organized crystalline Er silicate (Er(2)SiO(5)) films which show unique crystalline and 1.53 mu m emission characteristics totally different from those of Er-doped Si-based materials. The crystalline Er(2)SiO(5) exhibits a highly-oriented layered structure with a 0.86 nm period. Even with a high Er content (25at %), the material has few defects and less Er segregation. Er(3+) ions are considered to be Subjected to a uniform and strong crystal field, which results in almost single optically active Er(3+) centers and sharp photoluminescence peaks around 1.53 mu m with a Stark splitting even at room temperature. The material shows also a fast luminescent decay time (similar to 100 mu s or less), mainly due to the uniform and strong crystal field on Er(3+) ions. In this study, we describe various fabrication methods (sol-gel, MOMBE, laser ablation) of the Er silicate (Er(2)SiO(5)) films on Si substrates, and show our recent results on the crystalline and optical properties of Er(2)SiO(5). We also discuss the upconversion and a possibility of gain for a waveguide length less than 100 mu m.
International conference proceedings, English

Positive-bias enhanced growth of high quality diamond films by microwave plasma chemical vapor deposition
D. Saito; H. Isshiki; T. Kimura
DIAMOND AND RELATED MATERIALS, ELSEVIER SCIENCE SA, 18, 1, 56-60, Jan. 2009, Peer-reviwed, Enhancement was observed in the grain size, the growth rate and the (100) grain orientation of diamond films on Si (100) when a positive bias of 100-200 V was applied to the substrates during the microwave plasma chemical vapor deposition (MPCVD) of diamond films. The positive bias was found to be effective also for the growth of B-doped diamond films of good electrical properties. The hole Hall mobility of a diamond film grown with zero bias was around 100 cm(2)/V S while that of a sample with 200 V positive biasing reached 1000 cm(2)/V s. This mobility value belongs to the highest ever reported for diamond films on Si. The main effects of the positive bias during the MPCVD diamond growth were concluded to be a suppression of ion impinging into the substrate and an increased electron collision which would enhance the radical formation on the growing diamond films. (C) 2008 Elsevier B.V. All rights reserved.
Scientific journal, English

Fabrication and characterization of Er silicates on SiO2 /Si substrates
X. J. Wang; T. Nakajima; H. Isshiki; T. Kimura
Applied Physics Letters, 95, 4, 041906, 2009, Peer-reviwed, Er silicates have been fabricated on SiO2 /Si (100) substrates by the sol-gel method. In contrast to Si(100) substrates, on which the Er 2 SiO5 phase in general crystallizes, the α -Er 2 Si2 O7 with the photoluminescence (PL) main peak at 1531 nm formed at 1200°C. The integrated PL intensity of the α -Er2 Si2 O7 phase was about five to ten times stronger than that of the Er2 SiO5 phase, and the α -Er2 Si2 O7 phase showed a relatively long decay time (100-300 μs) in contrast to several tens of microseconds of the Er2 SiO5 phase. Excess O from SiO2 layer may lead to the formation of the α -Er2 Si2 O 7 phase. © 2009 American Institute of Physics.
Scientific journal, English

Toward Small Size Waveguide Amplifiers Based on Erbium Silicate for Silicon Photonics
H. Isshiki; T. Kimura
IEICE Transaction on Electronics, The Institute of Electronics, Information and Communication Engineers, E91, 2, 138-144, Feb. 2008, Peer-reviwed, Integration of light sources on a Si chip is one of milestone to establish new paradigm of LSI systems, so-called "silicon photonics." In recent years remarkable progress has been made in the Si wire waveguide technologies for optical interconnection on a Si chip. In this paper, several Er embedded materials based on silicon are surveyed from the standpoint of application to the light emission and amplification devices for silicon photonics. We have concentrated to investigate an erbium silicate (Er₂SiO₅) as a light source medium for silicon photonics. To mention the particular features, this material has a layered structure with 0.86-nm period and a large amount of Er (25at%) as its constituent. The single crystalline nature gives several remarkable properties for the application to silicon photonics. We also discuss our recent studies of Er₂SiO₅ and a possibility of the shorter waveguide amplifier.
Scientific journal, English

Demonstration of ErSiO superlattice crystal waveguide toward optical amplifiers and emitters
H. Isshiki; T. Ushiyama; T. Kimura
Physica Status Solidi (A) Applications and Materials Science, 205, 1, 52-55, Jan. 2008, Peer-reviwed, ErSiO superlattice crystal (SC) waveguide is demonstrated. ErSiO-SC film was formed on a SiO 2/Si substrate. After the ErSiO preform formation by sol-gel method, high temperature anneal for the crystallization was performed in Ar atmosphere. Then the ErSiO-SC layer thickness is 220 nm. Then refractive index of ErSiO-SC was estimated to be 1.8 by ellipsometry and reflection spectroscopy measurements. To obtain the lateral optical confinement, polymer cladding layer (n = 1.54) was coated on the ErSiO-SC film and the striploaded structures with 5 μm width were formed by focused ion beam (FIB) etching. The optical confinement factor F of the ErSiO-SC waveguide layer was estimated to be 0.42, assuming the lateral confinement factor was 1 because of the sufficient wide waveguide for the light. Optical pumping was performed by using a 1480 nm laser diode through the lensed fiber. The pumping power is 30 mW at the fiber input. Green light emissions corresponding to 4f intra-shell transitions from 4S 3/2 and 2H 11/2 to 4I 15/2 in the Er 3+ ions, indicating cooperative upconversion in the ErSiO-SC waveguide, can be observed by using a conventional CCD system at room temperature. The upconversion emission behaviour through the waveguide with a photon trap for the 1480 nm light reveals that the 1480 nm pumping light is well-confined into the waveguide. The cooperative upconversion as the gain limitting factor in the ErSiO-SC waveguide are discussed. © 2008 WILEY-VCH Verlag GmbH &
Co. KGaA.
International conference proceedings, English

シリコン発光デバイス-現状と展望-
木村 忠正; 一色 秀夫
光学, 37, 1, 14-20, Jan. 2008, Peer-reviwed
Scientific journal, Japanese

Structure and photoluminescence comparison of Er(2)SiO(5) and Er(2)O(3) prepared by sol-gel method
X. J. Wang; H. Isshiki; T. Kimura
2008 5TH IEEE INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS, IEEE, 96-98, 2008, Peer-reviwed, Two erbium compound films, Er(2)SiO(5) and Er(2)O(3) were fabricated by sol-gel method using two kinds of starting sol solutions, respectively, and corresponding structure and photoluminescence properties were studied.
International conference proceedings, English

Crystalline structure and luminescence properties of Er silicates fabricated on Si and SiO(2)/Si by the sol-gel method
T. Kimura; X. J. Wang; T. Nakajima; M. Ohe; T. Ushiyama; H. Isshiki
2008 5TH IEEE INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS, IEEE, 99-101, 2008, Peer-reviwed, Well-ordered Er(2)SiO(5) silicates with a fast decay (similar to 10 similar to 50 mu s) of the 1.53 mu m emission was obtained on Si by sol-gel. In contrast, Er silicates on SiO(2)/Si showed different luminescence spectra with a slow fluorescence decay (tau > 100 mu s).
International conference proceedings, English

Demonstration of ErSiO superlattice crystal waveguide toward optical amplifiers and emitters
H. Isshiki; T. Ushiyama; T. Kimura
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, WILEY-V C H VERLAG GMBH, 205, 1, 52-55, Jan. 2008, Peer-reviwed, ErSiO superlattice crystal (SC) waveguide is demonstrated. ErSiO-SC film was formed on a SiO2/Si substrate. After the ErSiO preform formation by sol-gel method, high temperature anneal for the crystallization was performed in Ar atmosphere. Then the ErSiO-SC layer thickness is 220 nm. Then refractive index of ErSiO-SC was estimated to be 1.8 by ellipsometry and reflection spectroscopy measurements. To obtain the lateral optical confinement, polymer cladding layer (n = 1.54) was coated on the ErSiO-SC film and the strip-loaded structures with 5 pin width were formed by focused ion beam (FIB) etching. The optical confinement factor F of the ErSiO-SC waveguide layer was estimated to be 0.42, assuming the lateral confinement factor was 1 because of the sufficient wide waveguide fort he light . Optical pumping was performed by using a 1480 nm laser diode through the lensed fiber. The pumping power is 30 mW at the fiber input. Green light emissions corresponding to 4f intra-shell transitions from S-4(3/2) and H-2(11/2) to I-4(15/2) in the Er3+ ions, indicating cooperative upconversion in the ErSiO-SC waveguide, can be observed by using a conventional CCD system at room temperature. The upconversion emission behaviour through the waveguide with a photon trap for the 1480 nm light reveals that the 1480 nm pumping light is well-confined into the waveguide. The cooperative upconversion as the gain limitting factor in the ErSiO-SC waveguide are discussed. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Scientific journal, English

シリコンをベースとする発光デバイス-現状と展望-
一色 秀夫; 木村 忠正
レーザー科学, 35, 9, 566-571, 2007, Peer-reviwed
Scientific journal, Japanese

Study on crystalline properties of Er-Si-O compounds in relation to Er-related 1.54 mu m photoluminescence and electrical properties
Tadamasa Kimura; Katsuaki Masaki; Hideo Isshiki
JOURNAL OF LUMINESCENCE, ELSEVIER SCIENCE BV, 121, 2, 226-229, Dec. 2006, Peer-reviwed, Er-Si-O crystalline compounds, which exhibit superlattice structures and sharp and strong Er-related 1.54 mu m photoluminescence (PL) spectra at room temperature have been formed by self-assembling growth mechanism. Oxidation of the starting materials which have Si and Er at an atomic ratio of 2:1 are prepared and then oxidation and succeeding high-temperature annealing in Ar above 1250 degrees C cause a self-assembled superlattice-structured Er-Si-O crystalline compounds. The control of the ratio of Si and Er, as well as the following oxidation and annealing processes, is found to be sensitive to the crystalline properties, PL spectra and electrical properties. In this study, Eri crystalline thin films are formed on Si substrates by sol-get and MOMBE methods, and their crystalline properties such as crystalline orientation and concentration ratio of Er, Si and 0 are investigated. Crystalline Er-Si-O films of high orientation are successfully grown on Si(1 0 0) and its inclined surface. The PL and excitation spectra, fluorescence decay and the electrical properties are found to be strongly related to the crystalline properties. Excess 0 causes a broader 1.54 mu m PL spectra, slower fluorescence decay, lower carrier-mediated excitation and higher resistivity. A precise control of 0 is found to be necessary to grow superlattice-structu red Eri compounds, which are semiconducting and are excitable via carrier-mediated excitation mechanism. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English

Towards epitaxial growth of ErSiO nanostructured crystalline films on Si substrates
H Isshiki; K Masaki; K Ueda; K Tateishi; T Kimura
OPTICAL MATERIALS, ELSEVIER SCIENCE BV, 28, 6-7, 855-858, May 2006, Peer-reviwed, ErSiO nanostructured crystalline films were obtained by the self-organization process at above 1200 degrees C so far. We are studying on the epitaxial growth of ErSio nanostructured crystalline films on Si substrates with views to reducing the process temperature and controlling the superstructures with layer by layer. In this paper, metal organic molecular beam epitaxy (MOMBE) growth of ErSiO nanostructured crystalline films on 15 degrees off Si(1 0 0) substrates at 900 degrees C are demonstrated. Tetra ethoxy silane (TEOS) and 2,2,6,6-tetra methyl-3,5octane dionat erbium (Er(TMOD)(3)) were used as Si-O and Er-O precursors, respectively. The X-ray diffraction result indicates the crystallization under lower temperature than the self-organization. The PL fine structure of Er-related emissions originated from the crystalline nature was observed in the as-grown ErSiO nanostructured crystalline films at room temperature. Also we discuss the possibility of hetero epitaxial growth of ErSiO nanostructured crystalline films on off-oriented Si(1 0 0) substrates from the results. (c) 2005 Elsevier B.V. All rights reserved.
Scientific journal, English

The effect of annealing conditions on the crystallization of Er-Si-O formed by solid phase reaction
K Masaki; H Isshiki; T Kawaguchi; T Kimura
OPTICAL MATERIALS, ELSEVIER SCIENCE BV, 28, 6-7, 831-835, May 2006, Peer-reviwed, Er-Si-O crystal is one of the promising materials for Si-based opto-electronic devices. Crystallization of Er-Si-O is obtained by solid phase reaction of an amorphous preform which contains Er-O and Si-O bonds. However detailed crystallization mechanism is not clear. This study reports that the control of oxygen content of the sample in the annealing process for crystallization affects the fine arrangements of Er-Si-O crystals, resulting in three different types of XRD patterns and correspondingly different PL spectrum fine structures.
The sol-gel method was used to prepare the amorphous preform. The samples were then annealed at 1250 degrees C in Ar for the solid phase growth of Er-Si-O crystals. The obtained Er-Si-O crystals showed, however, some different types of XRD patterns and the PL spectra. It was speculated that a slight amount of residual oxygen in the annealing furnace affected the Er-Si-O crystal structure. To study the effect of oxygen, during solid phase growth three processes were applied; putting a Si cap on the sample to reduce the influence of the atmosphere, additionally putting a carbon sheet as oxygen getter on the sample covered with a Si cap and no Si capping. Three kinds of XRD patterns, PL spectrum fine structures, PLE spectra and PL time decays were observed, depending on the three processes. These results indicate that the fine arrangements of Er-Si-O crystals are affected by oxygen content in the crystal which is very sensitive to oxygen in the annealing Ar atmosphere during the solid phase growth and their properties are come from their particular crystalline structures. (c) 2005 Elsevier B.V. All rights reserved.
Scientific journal, English

Quasi-coherence and the field effect in Ga(As,P) “fractal” superlattice for functional photonic devices
H. Isshiki
ECTI-ECC Transactions, 4, 1, 56, 2006, Peer-reviwed
Scientific journal, English

Upconversion emission from ErSiO superlattice crystal waveguide
H. Isshiki; T. Ushiyama; T. Kimura
2006 3RD IEEE INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS, IEEE, 67-+, 2006, Peer-reviwed, ErSiO superlattice crystal waveguide is demonstrated. Due to the optical confinement effect, upconversion emission can be observed. From the upconversion the light propagation properties in the waveguide discussed.
International conference proceedings, English

ErSiO self-organized superlattice crystals as a 1.54μm luminescent material
T. Kimura; H. Isshiki
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS, 2005, 766-767, 2005, Peer-reviwed, ErSiO crystals with 17% Er contents were formed on Si. Their growth methods, superlattice structures, 1.54μm fine photoluminescence and photoexcitation spectra with Stark splitting at room temperature and small thermal quenching characteristics will be presented. © 2005 IEEE.
International conference proceedings, English

ErSiO self-organized superlattice crystals as a 1.54 mu m luminescent material
T Kimura; H Isshiki
2005 IEEE LEOS Annual Meeting Conference Proceedings (LEOS), IEEE, 765-766, 2005, Peer-reviwed, ErSiO crystals with 17% Er contents were formed on Si. Their growth methods, superlattice structures, 1.54 mu m fine photoluminescence and photoexcitation spectra with Stark splitting at room temperature and small thermal quenching characteristics will be presented.
International conference proceedings, English

Semiconducting nature of ErSiO crystalline compounds with superlattice structure
H Isshiki; K Masaki; T Kawaguchi; T Kimura
2005 2nd IEEE International Conference on Group IV Photonics, IEEE, 77-78, 2005, Peer-reviwed, Semiconducting nature of ErSiO crystalline compounds with superlattice structure is revealed by photocurrent excitation (PCE) and Photoluminescence excitation (PLE) measurement.
International conference proceedings, English

Electronic structures of B 2p and C 2p levels in boron-doped diamond films studied using soft x-ray absorption and emission spectroscopy
J Nakamura; E Kabasawa; N Yamada; Y Einaga; D Saito; H Isshiki; S Yugo; RCC Perera
PHYSICAL REVIEW B, AMERICAN PHYSICAL SOC, 70, 24, 245111, Dec. 2004, Peer-reviwed, X-ray absorption (XAS) and emission (XES) spectroscopy near B K and C K edges have been performed on metallic (similar to0.1 at. % B, B-diamond) and semiconducting (similar to0.03 at. % B and N, BN-diamond) doped diamond films. Both B K XAS and XES spectra show a metallic partial density of states (PDOS) with the Fermi energy of 185.3 eV, and there is no apparent boron-concentration dependence in contrast to the different electric property. In C K XAS spectrum of B-diamond, the impurity state ascribed to boron is clearly observed near the Fermi level. The Fermi energy is found to be almost same with the top of the valence band of nondoped diamond: E-V=283.9 eV. C K XAS of BN-diamond shows both the B-induced shallow level and N-induced deep and broad levels as the in-gap states, in which the shallow level is in good agreement with the activation energy (E-a=0.37 eV) estimated from the temperature dependence of the conductivity; namely, the change in C 2p PDOS of impurity-induced metallization is directly observed. The electric property of this diamond is ascribed mainly to the electronic structure of C 2p near the Fermi level. The observed XES spectra are compared with the discrete variational Xalpha (DVXalpha) cluster calculation. The DVXalpha result supports the strong hybridization between B 2p and C 2p observed in XAS and XES spectra, and suggests that the small amount of boron (less than or equal to0.1 at. %) in diamond occupies the substitutional site rather than interstitial site.
Scientific journal, English

Self-assembled infrared-luminescent Er-Si-O crystallites on silicon
H Isshiki; MJA de Dood; A Polman; T Kimura
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 85, 19, 4343-4345, Nov. 2004, Optically active and electrically excitable erbium complexes on silicon are made by wet-chemical synthesis. The single-crystalline Er-Si-O compound is formed by coating a Si(100) substrate with an ErCl3/ethanol solution, followed by rapid thermal oxidation and annealing. Room-temperature Er-related 1.53 mum photoluminescence is observed with a peak linewidth as small as 4 meV. The complexes can be excited directly into the Er intra-4f states, or indirectly, through photocarriers. Er concentrations as high as 14 at. % are achieved, incorporated in a crystalline lattice with a 0.9 nm periodicity. Thermal quenching at room temperature is only a factor 5, and the lifetime at 1.535 mum is 200 mus. (C) 2004 American Institute of Physics.
Scientific journal, English

Erbium-silicon-oxide crystalline films prepared by MOMBE
K. Masaki; H.Isshiki; T.Kimura
Optical Materials, 27, 876, 2004, Peer-reviwed
Scientific journal, English

Erbium-silicon-oxide nano-crystallite waveguide formation based on nano-porous silicon
T. Kimura; K. Ueda; R. Saito; K. Masaki; H. Isshiki
Optical Materials, 27, 880-883, 2004, Peer-reviwed
Scientific journal, English

Structural and optical properties of Mg(x)Znl(1-x)O thin films formed by sol-gel method
T Murakawa; T Fukudome; T Hayashi; H Isshiki; T Kimura
5TH INTERNATIONAL SYMPOSIUM ON BLUE LASER AND LIGHT EMITTING DIODES, PROCEEDINGS, WILEY-V C H VERLAG GMBH, 1, 2564-2568, 2004, Peer-reviwed, MgxZn1-xO thin film alloys were formed on Si substrates by a sol-gel method. The percentage of Mg was controlled by the mol ratio in the starting alcoholate sol solution. The structure of films was studied by X-ray diffraction (XRD). The grain morphology and their spatial compositions were measured by scanning electron microscopy (SEM) together with energy dispersive X-ray spectrometry (EDS) analysis. The films were found to be composed of grains of around several ten nanometers in size and different Mg contents. The photoluminescence (PL) shows a bandedge emission with its peak energy changing from 3.3 eV to 3.6 eV for the Mg content of the starting alcoholate solution from 0% to 20%. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
International conference proceedings, English

1.5 mu m PL fine structures and their extreme fast decay of crystalline ErSiO compounds
H Isshiki; K Masaki; K Ueda; R Saito; T Kimura
2004 IST IEEE INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS, IEEE, 192-193, 2004, Peer-reviwed, Er-related 1.5 mu m emissions with linewidth of less than 1meV and 10 mu s lifetime have been observed in crystalline ErSiO superstructures.
International conference proceedings, English

Erbium-silicon-oxide thin films formed by sol-gel method
K Masaki; H Isshiki; T Kimura
2004 IST IEEE INTERNATIONAL CONFERENCE ON GROUP IV PHOTONICS, IEEE, 95-97, 2004, Peer-reviwed, This paper presents strong and sharp Er-related 1.53 mum photoluminescence characteristics and crystalline properties of Er-Si-O thin films formed by sol-gel method.
International conference proceedings, English

Preferential suppression of Auger energy backflow by separation of Er ions from carriers with a thin oxide interlayer in Er-doped porous silicon
T Kimura; H Isshiki; T Ishida; T Shimizu; S Ide; R Saito; S Yugo
JOURNAL OF LUMINESCENCE, ELSEVIER SCIENCE BV, 102, 156-161, May 2003, Peer-reviwed, Strong enhancement of the Er-related 1.54 mum emission was obtained at room temperature from Er-doped porous silicon (PSi), when host PSi was slightly preoxidized at 900degreesC before Er incorporation. It was speculated that the formation of the oxide interlayer played an important role. Separate measurements of the energy transfer and the Auger deexcitation between carriers in Si crystallites and Er ions were carried out using a two-beam (cw and pulse) excitation method for various preoxidation time which was supposed to change the oxide interlayer thicknesses from about 1 to 10 nm. It was found that a very thin SiO2 interlayer between Si crystallites and Er. ions suppressed preferentially the Auger deexcitation to the carrier-mediated Er excitation. A thin SiO2 interlayer was also effective to suppress the phonon-assisted energy backtransfer at high temperatures (so-called temperature quenching). This preferential suppression of the energy backflow (both Auger deexcitation and temperature quenching) by a thin oxide interlayer led to a strong room temperature. Er-related emission at 1.54 mum in Er-doped porous silicon. The Er/SiO2/Si structure was also formed on a flat Si surface and quite the same result was obtained. The oxide interlayer thickness of similar to2 nm was found optimum to suppress the energy backflow sufficiently with only a slight decrease in the carrier-mediated excitation of Er ions. (C) 2002 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Optical characterization of Er-implanted ZnO films formed by sol-gel method
T. Fukudome; A. Kaminaka; H. Isshiki; R. Saito; S. Yugo; T. Kimura
Nucl. Instr. , Meth. in Phys. Res. B, 206, 287-290, May 2003, Peer-reviwed
Scientific journal, English

Fine structure in the Er-related emission spectrum from Er-Si-O matrices at room temperature under carrier mediated excitation
H Isshiki; A Polman; T Kimura
JOURNAL OF LUMINESCENCE, ELSEVIER SCIENCE BV, 102, 819-824, May 2003, Peer-reviwed, Er-Si-O crystalline matrices (ESO) have been synthesized by coating the Si surface with an ErCl/ethanol solution, followed by a two-step annealing process, first in oxygen and second in argon. Fine structures of the Er3+-related photoluminescence (PL) spectrum (line width less than 4 meV) have been observed at room temperature. The PL fine structures indicate Stark splitting of the 4f-electron energy levels in erbium ions. The PL excitation spectrum at room temperature shows the carrier-mediated excitation of Er ions. These results suggest that ESO are of a stable and homogeneous structure in semiconducting silicon matrix and are optically very active. The local environment of erbium ions is discussed from the Stark splitting. (C) 2002 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Suppression of Auger deexcitation and temperature quenching of the Er
Tadamasa Kimura; Hideo Isshiki; Sawa Ide; Takanori Shimizu; Takeshi Ishida; Riichiro Saito
Journal of Applied Physics, 93, 5, 2595-2601, Mar. 2003, Peer-reviwed
Scientific journal, English

Erbium-silicon-oxide nano-complexes prepared by wet chemical synthesis
H Isshiki; MJA de Dood; T Kimura; A Polman
OPTOELECTRONICS OF GROUP-IV-BASED MATERIALS, MATERIALS RESEARCH SOCIETY, 770, 133-138, 2003, Peer-reviwed, An entirely new method to fabricate optically active and carrier-mediated excitable erbium complexes on silicon is presented. The Er-Si-O nano-complexes are formed by spin-coating a Si (100) substrate with an ErCl3 solution, followed by a rapid thermal oxidation and annealing sequence (RTOA). Intense room-temperature luminescence is observed from the Er-Si-O nano-complexes, with a line width as narrow as 4 meV at room temperature. The Er emission at 1.53 mum can be excited both directly and through photo carriers. Formation and optical activation of the Er-Si-O nano-complexes are discussed. In addition, an application of the wet chemical synthesis technique to incorporation of the Er-Si-O nano-complexes into nano-porous silicon waveguides is demonstrated.
International conference proceedings, English

Ge dot formation on Si by MOVPE using tetramethylgermanium (Ge(CH3)(4))
M Ohtake; M Wada; M Sugiyama; H Isshiki; R Saito; S Yugo; T Kimura
2ND INTERNATIONAL CONFERENCE ON SEMICONDUCTOR QUANTUM DOTS, WILEY-VCH, INC, 1113-1116, 2003, Peer-reviwed, Ge dot formation on Si(100) in metal organic vapor phase epitaxy (MOVPE) using tetramethylgermanium (TMGe) as the Ge source is demonstrated. The dots were formed in the growth temperature range between 600 and 700 degreesC. Atomic force microscopy measurement indicates that Ge dots grow in the Stranski-Krastanov mode. By comparison of the aspect ratio of the dots to those obtained by other growth methods, it is shown that the Ge dot formation mechanism and the resulting dot shape depend on the atmosphere during the dot formation.
International conference proceedings, English

Study of the radiative and nonradiative processes of rare earth implanted semiconductors at low temperatures
T Kimura; H Toda; T Ishida; H Isshiki; R Saito
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, ELSEVIER SCIENCE BV, 175, 286-291, Apr. 2001, Peer-reviwed, Factors determining the low temperature fluorescent transition rate of the luminescence of rare earth implanted semiconductors are studied. Photocarrier induced Auger deexcitation has been used to separate the radiative transition rate from the fluorescent one for Er-, Er and Ne-, Er and O-implanted Si and He-implanted GaAs. (C) 2001 Elsevier Science B.V. All rights reserved.
Scientific journal, English

偏光ラマン散乱による原子層超格子構造の無秩序化の評価
飯塚 博; 一色秀夫; 齋藤理一郎; 木村忠正
第48回応用物理学関係連合講演会，明治大学, Mar. 2001
Japanese

ゾルーゲル法により作製した希土類添加ZnOの可視域発光
上中敦史; 佐藤隆史; 石田 猛; 一色秀夫; 齋藤理一郎; 湯郷成美; 木村忠正
第48回応用物理学関係連合講演会，明治大学, Mar. 2001
Japanese

Luminescence from Er-doped Si film grown by solid phase epitaxy
T. Kobayashi; S. Komuro; H. Sone; S. Shimoda; H. Isshiki, T; Katayama; M. Aono
RIKEN Review, 38, 23-25, 2001, Peer-reviwed
Research institution, English

Perfect "fractal" behavior in XRD pattern of Ga(As,P) Fibonacci lattice grown by atomic layer epitaxy
H Isshiki; JS Lee; Y Aoyagi; T Sugano
JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, 221, 37-40, Dec. 2000, Peer-reviwed, Fractal behavior in X-ray diffraction (XRD) from a Ga(As, P) fractal-structured lattice grown by atomic layer epitaxy (ALE) has been discussed. Fibonacci progression for the 11th generation was used as the fractal arrangement of lattice. Self-similar geometry particular to fractal has been confirmed by a conventional XRD measurement system using CuKx1 radiation. In addition, the XRD spectrum shows a good agreement with the result of fast-Fourier transform (FFT) analysis, and the perfect fractal behavior for the 11th generated lattice arrangement. We can conclude that ALE is the most powerful tool for synthesis of the fractal-structured lattice. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Highly erbium-doped zinc-oxide thin film prepared by laser ablation and its 1.54 mu m emission dynamics
S Komuro; T Katsumata; T Morikawa; XW Zhao; H Isshiki; Y Aoyagi
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 88, 12, 7129-7136, Dec. 2000, Peer-reviwed, Erbium-doped ZnO (ZnO:Er) thin films were fabricated by the KrF excimer laser ablation technique, which is a useful and simple technique to dope Er atoms on the order of 10(20) cm(-3) into a host material. As-prepared ZnO:Er films showing strong c-axis orientation with a hexagonal crystalline structure indicate a low electrical resistivity of 6.4x10(-3) Omega cm. The sharp and intense photoluminescence (PL) at 1.54 mum originating from the intra-4f transition in the Er3+ ions as well as PL in UV region from the ZnO host were observed even at room temperature. Significant distinction arising from the different Er emission centers responsible for the 1.54 mum emission cannot be found in the temperature dependence between the ZnO:Er and Si:Er film as a reference, except for the PL spectrum feature and main PL peak position. This result suggests the existence of Er emission centers in ZnO:Er and Si:Er films that are different from each other. The details of Er-related 1.54 mum emission dynamics of ZnO:Er films have been investigated for the different excitation conditions, where the Er3+ ions have been excited either through a carrier-mediated process in the ZnO host, or through direct pumping into the 4f energy level of the Er3+ ions. There is no change in the 1.54 mum PL spectrum feature in spite of the different excitation conditions, whereas a sensible change can be seen in the rise time of the 1.54 mum emission. The shorter rise time of the 1.54 mum emission observed for indirect excitation implies an excitation efficiency superior to the direct excitation of Er3+ ions. This result indicates that the ZnO:Er thin films are expected to be a promising infrared optoelectronic materials candidate for carrier injection devices because of the high electrical conductivity and high excitation efficiency of the Er3+ ions of an electron-hole-mediated process resulting from ZnO host excitation. (C) 2000 American Institute of Physics. [S0021-8979(01)03201-7].
Scientific journal, English

Study of the radiative and nonradiative processes of rare earth implanted semiconductors at low temperatures
T. Kimura; H. Toda; T. Ishida; H. Isshiki; R. Saito
IBMM2000, Porto Alegre, Brasil, Sep. 2000
English

ゾルーゲル法により作製したEr添加ZnOにおけるEr^3+^の発光
石田 猛; 上中敦史; 一色秀夫; 齋藤理一郎; 湯郷成美; 木村忠正
第61回応用物理学会学術講演会，北海道工業大学, Sep. 2000
Japanese

多孔質Si膜中に形成したEr/SiO_2_/Si構造からの1.54μmPL発光
一色秀夫; 清水隆範; 井手佐和; 木村忠正
第61回応用物理学会学術講演会，北海道工業大学, Sep. 2000
Japanese

Direct evaluation of atomic layer intermixing via disordering in ALE grown (GaAs)(m)(GaP)(1) system
H Isshiki; M Takahashi; N Yamane; H Iizuka; Y Aoyagi; T Sugano; T Kimura
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 159, 508-513, Jun. 2000, Peer-reviwed, Atomic layer intermixing at pseudomorphic interfaces has been evaluated directly by changing of electronic states due to disordering in (GaAs)(m)(GaP)(1) (m = 2, 3, 4) superlattice grown by atomic layer epitaxy (ALE). The results show the critical change of the electronic structures due to atomic layer intermixing at GaAs/GaP hetero interface. The interdiffusion coefficients are about two orders of magnitude higher than values of the self-diffusion. It is suggested that microscopic and inhomogeneous strain effects are closely related to the exchange of neighboring atoms at the interface. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

1.54 mu m emission dynamics of erbium-doped zinc-oxide thin films
S Komuro; T Katsumata; T Morikawa; Zhao, X; H Isshiki; Y Aoyagi
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 76, 26, 3935-3937, Jun. 2000, Erbium-related 1.54 mu m emission dynamics of Er-doped ZnO thin films has been investigated for the different excitation conditions. The excitation was achieved either by exciting indirectly Er3+ ions due to an electron-hole-mediated process or exciting directly discrete energy levels of Er3+ ions. There is no change in the 1.54 mu m emission spectrum feature in spite of the different excitation conditions, whereas dramatic change can be seen in the rise time of 1.54 mu m emission. The shorter rise time of 1.54 mu m emission observed for indirect excitation implies an excitation efficiency superior to direct excitation of Er3+ ions. (C) 2000 American Institute of Physics. [S0003-6951(00)03226-5].
Scientific journal, English

Site of the Er3+ optical centers of the 1.54 mu m room-temperature emission in Er-doped porous silicon and the excitation mechanism
W Wang; H Isshiki; S Yugo; R Saito; T Kimura
JOURNAL OF LUMINESCENCE, ELSEVIER SCIENCE BV, 87-9, 319-322, May 2000, Peer-reviwed, Sites of the Er3+ luminescent centers in Er-doped porous silicon (PS:Er) formed by immersion are studied in order to make clear the cause of the strong room temperature luminescence at 1.54 mu m due to the 4f intra-transition of Er3+ ions. The luminescence spectra and the temperature quenching of the intensity and the fluorescence lifetime are compared between PS:Er samples formed by immersion in an ErCl3/alcohol solution and Er-implanted PS, using the same PS hosts. PS:Er samples formed by immersion show a small temperature quenching in the intensity and the fluorescence lifetime, resulting in a strong luminescence at RT. On the other hand, PS:Er samples formed by Er ion implantation into PS shows almost the same strong temperature quenching as the Er-implanted crystalline Si. These results indicate that the sites of Er ions responsible for the strong RT 1.54 mu m luminescence in PS:Er formed by immersion is not inside Si nanocrystals but on the surface of Si nanocrystals. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Fabrication and optical transition dynamics of Er-doped ZnO thin films formed on Si substrates
Zhao, X; S Komuro; H Isshiki; Y Aoyagi; T Sugano
JOURNAL OF LUMINESCENCE, ELSEVIER SCIENCE BV, 87-9, 1254-1256, May 2000, Peer-reviwed, Er-doped ZnO (ZnO :Er) thin films fabricated on Si substrates were investigated by photoluminescence (Pt) and PL excitation (PLE) spectroscopy. The ZnO : Er thin films emit sharp and intense 1.54 mu m luminescence. It is shown that the Er-related PL gives rise to different features under direct and indirect excitations. An over band-gap excitation leads to a faster lifetime of the 1.54 mu m PL indicating a strong interaction of electron-hole pairs in the host with 4f electrons in the Er3+ ions. The ZnO:Er is a promising candidate for optoelectronic devices excited by carrier injection because of its high electrical conductivity. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Photo-reflectance study on Ga(As,P) fractal-structured lattice
H Isshiki; Y Aoyagi; T Sugano
MICROELECTRONIC ENGINEERING, ELSEVIER SCIENCE BV, 51-2, 157-163, May 2000, Peer-reviwed, Subband formation in fractal-structured lattice (FSL) has been investigated by photo-reflectance (PR) measurements. Ga(As,P) FSL was grown on a (001) GaAs substrate by atomic layer epitaxy (ALE). Fibonacci progression for the 11th generation was used as the fractal arrangement of lattice. The X-ray diffraction shows no periodicity but long-range order. The PR spectra show formation of the singular subband originating from the fractal lattice arrangement, and are consistent with a transfer matrix calculation on the FSL. These results suggest that the FSL arrangement can cause interference of electron wave function in the FSL. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Formation and device application of Er-doped nanocrystalline Si using laser ablation
XW Zhao; H Isshiki; Y Aoyagi; T Sugano; S Komuro
MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY, ELSEVIER SCIENCE SA, 74, 1-3, 197-201, May 2000, Peer-reviwed, Laser ablation is a successful process to fabricate Er-doped nanocrystalline Si (nc-Si) thin films with high doping densities. The formed samples show intense 1.54 mu m emission at room temperature. The high doping density of Er and the widening effect of the bandgap of the host nc-Si caused by fabricating Si in the nanometer scale give rise to a remarkable increase of the emission intensity of Er at room temperature. The time-response measurements under direct and indirect excitations reveal that the Er3+ ions doped in nc-Si are dominantly excited by an energy transfer process from the photo-generated electron-hole pairs. This gives hope to realizing the Si-based optical devices by current injection. (C) 2000 Elsevier Science S.A. All rights reserved.
Scientific journal, English

Si添加したEr^3+^イオンの励起過程における中間準位の解明―電界パルスによる中間準位の電子正孔対解離効果―
武田健太郎; 上中敦史; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第47回応用物理学関係連合講演会，2000.3.28-31，青山学院大学, Mar. 2000
Japanese

酸素共添加ErドープSi発光の光励起キャリアによるオージェクエンチング
戸田博之; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第47回応用物理学関係連合講演会，2000.3.28-31，青山学院大学, Mar. 2000
Japanese

ErドープポーラスシリコンのPL発光における酸素プレアニール効果
井手佐和; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第47回応用物理学関係連合講演会，2000.3.28-31，青山学院大学, Mar. 2000
Japanese

Erドープ多孔質Siの発光特性に対する表面Si保護効果
清水隆範; 石山卓茂; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第47回応用物理学関係連合講演会，2000.3.28-31，青山学院大学, Mar. 2000
Japanese

Auger de-excitation of the 1.54 mu m emission of Er- and O-implanted silicon
T Nakanose; T Kimura; H Isshiki; S Yugo; R Saito
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, ELSEVIER SCIENCE BV, 161, 1080-1084, Mar. 2000, Peer-reviwed, This paper describes the Anger de-excitation of the Er3+-related 1.54 mu m luminescence of Er and O coimplanted silicon. Time response of the Er-related 1.54 mu m emission to 0.3 ns wide light pulses of the 337 nm N-2 laser line is measured under CW illumination of the Ar ion laser 488 nm line. O coimplantation is found to produce new Si:Er-O luminescence centers which illuminate at the same wavelength as Si:Er. but with a much shorter fluorescence lifetime. The time response of the Si:Er-O luminescence is found to be very sensitive to the Ar 488 nm CW illumination. Both the intensity and the fluorescence lifetime decrease rapidly with increase of the CW light intensity. The Auger coefficient of Er-O centers obtained is about ten times larger with respect to Si:Er. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

1540nm stimulated emission from Er-doped nanocrystalline Si waveguides formed on Si substrates
X. Zhao; S. Komro; H. Isshiki; Y. Aoyagi; T. Sugano
24^th^ International Conference on the Physics of Semiconductors（World Scientific Publishing, CO-ROM），0313.pdf, 0313, 2000, Peer-reviwed
Scientific journal, English

希土類ドープ半導体発光の光励起キャリアによるオージェクエンチング
戸田博之; J. F. Suyver; P. G. Kik; A. Polman; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
秋季第60回応用物理学会学術講演会，甲南大学, Sep. 1999
Japanese

Er ドープポーラスシリコンのPL発光における酸素プレアニール効果
井手佐和; 戸田博之; 武田健太郎; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
秋季第60回応用物理学会学術講演会，甲南大学, Sep. 1999
Japanese

Photoluminescence and optical transition dynamics of Er3+ ions in porous Si
XW Zhao; H Isshiki; Y Aoyagi; T Sugano; S Komuro
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, JOURNAL MATER SCI TECHNOL, 15, 4, 357-362, Jul. 1999, Peer-reviwed, Er was doped into porous Si by immersing the porous Si sample in a saturated ErCl3:ethanol solution. Sharp and intense 1.54 mu m photoluminescence caused by intra-4f-shell transitions in Er3+ ions was observed up to room temperature. It is shown that the immersing process is valid to dope Er in high concentration in porous Si. Time resolved study of the Er-doped porous Si revealed that the doped Er3+ ions are excited by energy transfer from photo-generated electron-hole pairs in the host. The energy back transfer process from the excited 4f-electrons in the Er3+ ion to the host is not a dominant factor to quench the Er-related emission in porous Si. Our results are well explained by a proposed model in which an intermediate state was introduced.
Scientific journal, English

Er ドープシリコンの発光におけるエネルギー伝達機構と酸素添加の効果
木村忠正; 中ノ瀬貴生; 戸田博之; 齋藤理一郎; 一色秀夫
第８回シリコンテクノロジー研究会「光るシリコン―プロセス・素子技術の新展開」,1999年4月23日，東京農工大学, 16-21, Apr. 1999
Japanese

Er ドープシリコンの発光におけるエネルギー伝達機構と酸素添加の効果
木村忠正; 中ノ瀬貴生; 戸田博之; 齋藤理一郎; 一色秀夫
第８回シリコンテクノロジー研究会「光るシリコン―プロセス・素子技術の新展開」,1999年4月23日，東京農工大学, Apr. 1999
Japanese

Ga（As,P）１次元フラクタル格子における電子状態
一色秀夫; 木村忠正; 青柳克信; 菅野卓雄
第46回効用物理学関係連合講演会，野田, Mar. 1999
Japanese

Er添加ZnO薄膜の作成と発光
小室修二; 森川滝太郎; 趙新為; 一色秀夫; 青柳克信
第46回効用物理学関係連合講演会，野田, Mar. 1999
Japanese

Er添加Si微粒子材料のPLE測定
小室修二; 森川滝太郎; 趙新為; 一色秀夫; 青柳克信; 菅野卓雄
第46回効用物理学関係連合講演会，野田, Mar. 1999
Japanese

Si中に熱拡散したErの発光スペクトル
山下 裕; 中ノ瀬貴生; 王 威; 戸田博之; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第46回応用物理学関係連合講演会，1999年3月28-31日，（東京理科大学）, Mar. 1999
Japanese

イオン注入法により作製したEr添加Siにおける1.54μm発光の時間応答(3)-CWレーザ照射下における時間応答特性-
山下 裕; 中ノ瀬貴生; 王 威; 戸田博之; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第46回応用物理学関係連合講演会，1999年3月28-31日，（東京理科大学）, Mar. 1999
Japanese

ErドープポーラスシリコンのEr発光中心サイト
王 威; 戸田博之; 井手佐和; 中ノ瀬貴生; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第46回応用物理学関係連合講演会，1999年3月28-31日，（東京理科大学）, Mar. 1999
Japanese

Hoドープシリコンにおける1.20μm 発光の温度特性
戸田博之; 中ノ瀬貴生; J. F. Suyver; P. G. Kik; A. Polman; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
春季第46回応用物理学関係連合講演会，1999年3月28-31日，（東京理科大学）, Mar. 1999
Japanese

非周期系超格子における電子状態のコヒーレント制御
一色秀夫; 木村忠正; 青柳克信; 菅野卓雄
理研シンポジウム"第二回コヒーレント科学"，和光市, Feb. 1999
Japanese

Time response of 1.54um emission from highly Er-doped nanocrystalline Si films prepared by laser ablation
S. Komuro; T. Katsumata; T. Morikawa; X. Zhao; H. Isshiki; Y. Aoyagi
Appl. Phys. Lett. 74, 120-122, 1999
English

Fabrication and stimulated emission of Er-doped nanocrystalline Si waveguides formed on Si substrates by laser ablation
XW Zhao; S Komuro; H Isshiki; Y Aoyagi; T Sugano
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 74, 1, 120-122, Jan. 1999, Peer-reviwed, Er-doped nanocrystalline Si (nc-Si) waveguides were fabricated on Si substrates and investigated by optical pumping. A stimulated emission at 1540 nm was demonstrated at room temperature. The sizes of the fabricated Er-doped nc-Si waveguides were 5000 nmX200 nmXL, where L is the cavity length and is changed from 1 to 10 mm. Superlinear optical outputs at 1540 nm were observed for the waveguides longer than 3 mm. The threshold of the optical output where the stimulated emission occurs is in the order of 10 MW/cm(2), and is demonstrated to depend on the cavity length of the waveguides. A large reduction of decay lifetimes of the light output from a cleavage facet of the Er-doped nc-Si waveguides was observed when the pumping power density exceeded the thresholds indicating an increase of transition probabilities in intra-4f electrons in Er3+ ions caused by the stimulated emission. Better 1540 nm laser performance and lower pumping power density should be obtained by optimizing the device structure and increasing the Er concentration. (C) 1999 American Institute of Physics. [S0003-6951(99)04301-6].
Scientific journal, English

Time response of 1.54 mu m emission from highly Er-doped nanocrystalline Si thin films prepared by laser ablation
S Komuro; T Katsumata; T Morikawa; XW Zhao; H Isshiki; Y Aoyagi
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 74, 3, 377-379, Jan. 1999, Peer-reviwed, Er-doped nanocrystalline Si thin films have been controllably prepared over the Er density of 10(19)-10(21) cm(-3) using a prescribed amount of Er in a bulk target by laser ablation. Intense photoluminescence at 1.54 mu m originating from intra-4f shell transitions in Er3+ ions has been observed. The increase of Er density cannot immediately result in a linear increase in Er3+-emission intensity. The time response measurement indicated that the change in the rise time of the Er3+ emission directly shows that Er3+ ions are excited by the energy transfer associated with the recombination of electron-hole pairs generated optically in the Si host. We found that the decrease of the excitation efficiency of Er3+ ions was responsible for the suppression of the Er3+-emission intensity in highly Er-doped nanocrystalline Si thin films. (C) 1999 American Institute of Physics. [S000-6951(99)02703-5].
Scientific journal, English

Energy transfer efficiency of the 1.54 mu m luminescence of Er-implanted silicon in relation to post-implantation annealing and impurity coimplantation
T Kimura; T Nakanose; W Wang; H Isshiki; R Saito
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, ELSEVIER SCIENCE BV, 148, 1-4, 486-491, Jan. 1999, CZ-Si (p-type, 0.1-0.2 Omega cm) is implanted with Er ions together with O or Ne ions. The 1.54 mu m photoluminescence (PL) intensity and the decay time are measured as Functions of ambient temperature From 20 to 200 K. The energy transfer efficiency from host Si to Er3+ 4f-electrons is derived from the above results and is found to be temperature dependent. In contrast to the almost temperature independency of the energy transfer efficiency for sufficiently annealed Er-implanted Si. it shows a decreasing tendency above 30-50 K when defects are introduced by Ne ion coimplantation, whereas it shows an increase above similar to 100 It when O ions are coimplanted. (C) 1999 Elsevier Science B.V. Ail rights reserved.
Scientific journal, English

Energy transfer efficiency of the 1.54 mu m luminescence of Er-implanted silicon in relation to post-implantation annealing and impurity coimplantation
T Kimura; T Nakanose; W Wang; H Isshiki; R Saito
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, ELSEVIER SCIENCE BV, 148, 1-4, 486-491, Jan. 1999, CZ-Si (p-type, 0.1-0.2 Omega cm) is implanted with Er ions together with O or Ne ions. The 1.54 mu m photoluminescence (PL) intensity and the decay time are measured as Functions of ambient temperature From 20 to 200 K. The energy transfer efficiency from host Si to Er3+ 4f-electrons is derived from the above results and is found to be temperature dependent. In contrast to the almost temperature independency of the energy transfer efficiency for sufficiently annealed Er-implanted Si. it shows a decreasing tendency above 30-50 K when defects are introduced by Ne ion coimplantation, whereas it shows an increase above similar to 100 It when O ions are coimplanted. (C) 1999 Elsevier Science B.V. Ail rights reserved.
Scientific journal, English

Time response of 1.54 mu m emission from highly Er-doped nanocrystalline Si thin films prepared by laser ablation
S Komuro; T Katsumata; T Morikawa; XW Zhao; H Isshiki; Y Aoyagi
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 74, 3, 377-379, Jan. 1999, Er-doped nanocrystalline Si thin films have been controllably prepared over the Er density of 10(19)-10(21) cm(-3) using a prescribed amount of Er in a bulk target by laser ablation. Intense photoluminescence at 1.54 mu m originating from intra-4f shell transitions in Er3+ ions has been observed. The increase of Er density cannot immediately result in a linear increase in Er3+-emission intensity. The time response measurement indicated that the change in the rise time of the Er3+ emission directly shows that Er3+ ions are excited by the energy transfer associated with the recombination of electron-hole pairs generated optically in the Si host. We found that the decrease of the excitation efficiency of Er3+ ions was responsible for the suppression of the Er3+-emission intensity in highly Er-doped nanocrystalline Si thin films. (C) 1999 American Institute of Physics. [S000-6951(99)02703-5].
Scientific journal, English

イオン注入ErドープポーラスシリコンのEr発光中心サイト
王 威; 戸田博之; 井手佐和; 中ノ瀬貴生; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
秋季第59回応用物理学会学術講演会（広島大学）, Sep. 1998
Japanese

イオン注入装置により作製したEr添加Siにおける1.54μm発光の時間応答(2)-Erイオンの励起過程に与える酸素共添加の影響-
中ノ瀬貴生; 戸田博之; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
秋季第59回応用物理学会学術講演会（広島大学），17p-R-2, Sep. 1998
Japanese

Hoドープシリコンの光学的および電気的特性
J. F. Suyver; P. G. Kik; A. Polman; G. Franzo; S. Coffa; 戸田博之; 一色秀夫; 齋藤理一郎; 木村忠正
秋季第59回応用物理学会学術講演会（広島大学），17p-R-7, Sep. 1998
Japanese

Er添加ナノ微結晶Si導波路からの1.54μmr誘導放出（Ｉ）
趙新為; 小室修二; 一色秀夫; 森川滝太郎; 青柳克信; 菅野卓雄
第59回応用物理学会学術講演会，広島, Sep. 1998
Japanese

ErドープSi微粒子の1.54μm 発光(7)-Erイオン励起過程のEr濃度依存性-
一色秀夫; 趙新為; 小室修二; 森川滝太郎; 青柳克信; 菅野卓雄
第59回応用物理学会学術講演会，広島, Sep. 1998
Japanese

Conduction subband formation in GaAsmGaPn Fractal Structured atomic-layer-superlatiice grown by atimic layer epitaxy
H. Isshiki; K. Tanaya; T. Kimura; J. S. Lee; Y Aoyagi; T. Saito
24rd International Conference on the Physicas of Semiconductors，August 2-7，1998，（Jerusalem, Israel）, Aug. 1998
English

1540nm stimulated emission from Er-doped nanocrystalline Si waveguides formed on Si substrates
X. Zhao; S. Komuro; H. Isshiki; Y. Aoyagi; T. Saito
24rd International Conference on the Physicas of Semiconductors，August 2-7，1998，（Jerusalem, Israel）, Aug. 1998
English

Energy Transfer Efficiency of the 1.54μm Luminescence of Er-Implanted Silicon in Relation to Post-Implantation Annealing and Impurity Coimplantation
T. Kiumura; T. Nakanose; W. Wang; H. Isshiki; R. Saito
IBMM98 Amsterdam, Aug. 1998
English

(GaAs)(m)(GaP)(n) low dimensional short-period superlattice fabricated by atomic layer epitaxy
H Isshiki; Y Aoyagi; T Sugano
MICROELECTRONIC ENGINEERING, ELSEVIER SCIENCE BV, 43-4, 301-307, Aug. 1998, The fabrication of (GaAs)(m)(GaP)(n) low dimensional short-period superlattices (LD-SPSL) by using advanced atomic layer epitaxy (ALE) techniques is demonstrated. (GaAs)(m)(GaP)(n) SPSL were grown on V-grooved GaAs substrates by using the ALE growth mode switching technique, between anisotropic (for GaAs growth) and isotropic (for Gap growth) ALE. The lateral confined systems composed of well-defined (GaAs),(GaP), SPSL have been confirmed via transmission electron microscopy (TEM). The zone-folding effect has been observed in the (GaAs),(GaP), LD-SPSL via photoluminescence (PL) measurements. Also multi-quantum wire structures (MQWR) composed by (GaAs)(m)(GaAs0.8P0.2)(n) SPSL, which were strong-coupled (m = 20, n = 5) and weak-coupled (m = 20, It = 20) systems, were fabricated. The coupling and the lateral confinement effects have been clearly observed via PL and PL excitation measurements. (C) 1998 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Time resolved study on 1.54μm emisson of Er-implanted Si
T. Nakanose; H. Isshiki; T. Kimura
17th Electronic Materials Symposium, Izu-Nagaoka, Jul. 1998
English

Effects of hydrogen plasma treatment on the 1.54 mu m luminescence of erbium-doped porous silicon
T Dejima; R Saito; S Yugo; H Isshiki; T Kimura
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 84, 2, 1036-1040, Jul. 1998, Well resolved, sharp photoluminescence (PL) peaks of Er3+ (4f(11)) ions at similar to 1.54 mu m are obtained from Er-doped porous silicon (PS:Er) on which a hydrogen plasma treatment is carried out after electrochemical incorporation of Er3+ ions into porous silicon. The full width at half maximum (FWHM) of the 1.538 mu m main peak at 20 K is less than 1 nm, which is much smaller than that obtained from PS:Er samples annealed in a H-2 or O-2 flow (FWHM 7-10 nm), and is comparable to that of Er-doped crystalline silicon. The thermal quenching of the PL intensity is, however, relatively small, the PL intensity decreasing only by a factor of 10 from 20 to 300 K. (C) 1998 American Institute of Physics. [S0021-8979(98)03114-4].
Scientific journal, English

InGaAs/GaAs quantum nanostructure fabrication on GaAs (111)A vicinal substrates by atomic layer epitaxy
JS Lee; H Isshiki; T Sugano; Y Aoyagi
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 83, 10, 5525-5528, May 1998, Peer-reviwed, InGaAs/GaAs quantum wire (QWR) and dots were fabricated on GaAs (111)A vicinal substrates by the atomic layer epitaxy (ALE) technique. In0.25Ga0.75As QWR structures were formed on metalorganic vapor phase epitaxy grown homogeneous multiatomic height steps on GaAs (111)A vicinal substrates misoriented toward the [11(2) over bar] direction. In photoluminescence measurement only one spectrum, which shows strong polarization dependence, was observed. The result and its narrow full. width at half maximum of 10 meV imply that the elimination of the wetting layer and excellent size uniformity are realized by the ALE technique. Spontaneous alignment of InGaAs quantum dots was also achieved by the ALE method. Boxlike shaped dot arrays of which height is restricted by the step height indicate that the ALE growth on the(lll)A vicinal surface has an effect on not only the arrangement but also on the size and shape control of quantum nanostructures. (C) 1998 American Institute of Physics.
Scientific journal, English

Erドープポーラスシリコンの酸素プラズマ処理
出島 徹; 一色秀夫; 湯郷成美; 齋藤理一郎; 木村忠正
第45回応用物理学会春季講演，30pZQ/5，（東京工科大学，1998年3月30日）, Mar. 1998
Japanese

Size control of Si nanocrystallites formed in amorphous Si matrix by Er-doping
XW Zhao; S Komuro; S Fujita; H Isshiki; Y Aoyagi; T Sugano
MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY, ELSEVIER SCIENCE SA, 51, 1-3, 154-157, Feb. 1998, Si nanocrystallites formed in amorphous Si (a-Si) show intense blue luminescence at room temperature. The samples are fabricated by crystallization of a-Si thin films, which leads to a large size dispersion of the nanocrystallites due to a random distribution of strain fields in the a-Si phase. In this work, we demonstrate a process of controlling the crystallite size by doping Er in the a-Si layers. The doped Er atom introduces additional strain in the a-Si matrix and behaves as a nucleation center during the crystallization. It is demonstrated that the average size of the Si nanocrystallites is almost independent of the crystallization time for a certain Er concentration and a certain annealing temperature. By controlling the Er density and crystallization temperature, we have fabricated a series of nanocrystalline (nc) Si samples having the average sizes from 3 to 10 nm. The smallest size achieved here is 2.7 nm. A bright blue luminescence from the Si nanocrystallites as well as a 1.54 mu m emission from the doped Er3+ ions were observed up to room temperature. (C) 1998 Elsevier Science S.A. All rights reserved.
Scientific journal, English

Surface structure control of GaAs (111)A vicinal substrates by metal-organic vapor-phase epitaxy
JS Lee; H Isshiki; T Sugano; Y Aoyagi
JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, 183, 1-2, 43-48, Jan. 1998, Peer-reviwed, Periodic structures with high uniformity have been fabricated by metal-organic vapor-phase epitaxy on GaAs(111)A vicinal surfaces. Scanning electron microscope and atomic force microscope surface images show strict dependence on substrate off-direction, growth temperature (T-g), and V/III ratio. Giant steps with long-range continuity and high uniformity have been formed on GaAs (111)A substrates misoriented towards the [112] direction. In addition, the heights of the giant steps show the saturation at high T-g: and the value is independent of substrate off-angle, On the other hand, homogeneous zigzag steps have emerged on the substrate off toward the [001] azimuth after the growth at high T-g, whereas relatively rough steps were formed on both substrates at low T-g. The results indicate the growth-mode transition from step-flow to facet formation as growth temperature gets higher.
Scientific journal, English

Time decay characteristics of the Yb3+ - Related 0.98 mu m emissions in porous silicon
T Kimura; Y Nishida; T Dejima; R Saito; H Isshiki
MATERIALS AND DEVICES FOR SILICON-BASED OPTOELECTRONICS, MATERIALS RESEARCH SOCIETY, 486, 293-298, 1998, Enhanced emissions at 0.98 mu m of Yb3+ ions (F-2(6/2) --> F-2(7/2)) incorporated in porous silicon are obtained when the host porous silicon is pre-annealed in an O-2 containing atmosphere. Time decay characteristics are measured for the Yb3+-related 0.98 pm emissions as well as for the emissions of these host porous silicon between 20 K and 300 K. The decay of the Yb3+ peak at 20 K is characterized with a fast (similar to 30 mu s) and a slow decay time (less than or equal to similar to 400 mu s), whereas it is fitted with one slow decay time (similar to 390 mu s) at 300 K. The results are explained in terms of two optical centers: one has a fast fluorescent lifetime with a large temperature quenching, and the other has a slow fluorescent lifetime which is nearly constant between 20 K and 300 K.
International conference proceedings, English

Optical activation of erbium doped porous silicon by hydrogen plasma treatment
T Dejima; R Saito; S Yugou; H Isshiki; T Kimura
MATERIALS AND DEVICES FOR SILICON-BASED OPTOELECTRONICS, MATERIALS RESEARCH SOCIETY, 486, 287-292, 1998, Er3+-doped porous silicon (Er:PS) shows strong room temperature emissions at similar to 1.54 mu m. However, its spectrum is usually much broader than that of Er-doped crystalline silicon (full-width at half maximum - FWHM - is similar to 10 nm). It is probably because Er ions are located in amorphous phases. We report in this paper that strong and very sharp Er3+ 1.54 mu m emissions are obtained, when Er:PS samples are treated in a hydrogen plasma. Porous silicon layers are formed by anodic etching and then doped with Er3+ ions in an ErCl3/ethanol solution by an electrochemical method, and then treated in a hydrogen plasma at similar to 1000 degrees C from 0.5 min to 90 min for the optical activation. Several sharp peaks are observed at 20K, of which the strongest peak is located at 1.538 mu m with an FWHM less than 1 nm. This value is comparable to that obtained from Er3+-doped crystalline silicon formed by means of molecular beam epitaxy (MBE) or ion implantation. Comparisons are made among hydrogen plasma, argon plasma, H-2 flow and vacuum for the post-dope annealing atmosphere. Fourier-transform infrared (FT-IR) absorption and secondary ions mass spectrometry (SIMS) measurements are also carried out. We conclude that preferential etching of amorphous surface layers, and termination of dangling bonds of silicon nanocrystallites with hydrogen atoms and formation of Er-H complexes may be responsible for the strong and sharp Er3+-related luminescence.
International conference proceedings, English

High-magnetic-field-induced large blueshift and depopulation of a quasi-one-dimensional electron-hole system in p-type modulation-doped semiconductor quantum wires
S Nomura; H Isshiki; Y Aoyagi; T Sugano; K Uchida; N Miura
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 57, 4, 2407-2414, Jan. 1998, Magneto-optical effects in p-type modulation-doped semiconductor quantum wires are investigated up to 40 T. Heavy doping of holes above the light-hole-like state at 0 T enables us to observe both the heavy-and light-hole-like states in the photoluminescence. A large blueshift in the photoluminescence peak and depopulation of the light-hole-like states by magnetic fields are observed. A realistic self-consistent Hartree calculation reveals that the observed large blueshift is due to the indirect-gap formation induced by the impurity ions in the barrier.
Scientific journal, English

Photoluminescence and probe effect of Er-doped nanometer-sized Si materials
XW Zhao; S Komuro; H Isshiki; S Maruyama; Y Aoyagi; T Sugano
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 113, 121-125, Apr. 1997, Peer-reviwed, Er was doped into porous Si and nanocrystalline Si thin films. Sharp and intense photoluminescence at 1.54 mu m was observed up to room temperature. We demonstrate that Er3+ ions are excited by an energy transfer process from the excited electron-hole pairs in the host materials and no direct excitation of Er3+ ions can be observed. This fact suggests that the Er emission could be used as a probe to determine absorption edges of:he hosts. This idea was first applied to Er-doped porous Si. Identical excitation edges of the 1.54 mu m emission and the visible emission from porous Si have been demonstrated, We suggest that the method should also be valid for measuring the absorption edge of a nanometer-sized Si host material even if it is not luminescent.
Scientific journal, English

Multiatomic step formation with excellent uniformity on vicinal (111)A GaAs surfaces by metalorganic vapor-phase epitaxy
JS Lee; H Isshiki; T Sugano; Y Aoyagi
JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, 173, 1-2, 27-32, Mar. 1997, Peer-reviwed, Giant steps with high uniformity and continuity have been successfully formed by metalorganic vapor-phase epitaxy on GaAs(111)A vicinal surfaces for the application of quantum wire fabrication. The step height is more than 30 monoatomic layer at a growth temperature of 660 degrees C. The surface morphologies obtained from scanning electron microscopy and atomic force microscopy measurements show the straight steps on (111)A substrates misoriented toward <[ (2)over bar 11]> direction with high uniformity. Terrace uniformity and step continuity are improved as the off-angle increases. A straight section of a step exceeding 10 mu m was obtained on 4 degrees off-substrate. Fluctuation has also been suppressed within 1 monoatomic layer height on this vicinal substrate.
Scientific journal, English

Selective area growth at multi-atomic-height steps arranged on GaAs (111)A vicinal surfaces by atomic layer epitaxy
JS Lee; H Isshiki; T Sugano; Y Aoyagi
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 112, 132-137, Mar. 1997, Peer-reviwed, A quantum wire array has been fabricated on GaAs (111)A vicinal substrates by continuous growth of metalorganic vapor phase epitaxy (MOVPE) and atomic layer epitaxy (ALE). The formation of multi-atomic height steps with high uniformity and continuity has been achieved by MOVPE on GaAs (111)A vicinal substrates misoriented toward [<(2)over bar 11>] direction. In the ALE process, the growth rate of the GaAs layer on the (111)A terrace has been controlled with the source gas feeding sequence and the growth temperature. Growth suppression on the (111)A terrace and selective adsorption of source molecules at the step region has been confirmed. A GaAs/GaAs0.9P0.1 quantum wire structure has been fabricated on the (111)A vicinal surface using an ALE selective growth technique.
Scientific journal, English

Quantum wire structures incorporating (GaAs)(m)(GaP)(n) short-period superlattice fabricated by atomic layer epitaxy
H Isshiki; Y Aoyagi; T Sugano
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 112, 122-126, Mar. 1997, Lateral confined systems of (GaAs)(m)(GaP)(n) short-period superlattice (SPSL) fabricated by using atomic layer epitaxy (ALE), for composition control in quantum nano-structures, are demonstrated. (GaAs)(m)(GaP)(n) SPSL were grown on V-grooved GaAs substrates by the localized-ALE on nanometer scale. The lateral confined systems composed of well-defined (GaAs)(m)(GaP)(n) SPSL have been confirmed via transmission electron microscopy (TEM) and photoluminescence (PL) measurements. Also GaAs/(GaAs)(m)(GaP)(n)-SPSL quantum wire structures were fabricated by ALE growth, and composition control in the structures was successfully realized for the first time.
Scientific journal, English

Effects of active hydrogen on atomic layer epitaxy of GaAs
T. Meguro; H. Isshiki; J. S. Lee; S. Iwai; Y. Aoyagi
Applied Surface Science, Elsevier, 112, 118-121, 1997, Atomic layer epitaxy of GaAs employing thermally activated hydrogen molecules is reported. It is found that hydrogen molecules thermally activated in a high-temperature cell reduce the ALE temperature, while the activation energy of formation of the methyl-Ga surface from the As surface does not change. On the other hand, the activation energy of formation of the As surface from the methyl-Ga surface remarkably decreases in the active hydrogen flow, indicating that AsH 3 molecules dissociate into AsH x (x = 1 or 2) in the vapor phase.
Scientific journal, English

Room-temperature luminescence from erbium-doped silicon thin films prepared by laser ablation
S Komuro; S Maruyama; T Morikawa; XW Zhao; H Isshiki; Y Aoyagi
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 69, 25, 3896-3898, Dec. 1996, Peer-reviwed, We present a useful and simple technique to prepare controllable Er-doped Si thin films using KrF excimer laser ablation. The sharp intense photoluminescence (PL) at 1.54 mu m originating from the intra-4f shell transition in Er3+ ions was observed from 18 K up to room temperature. Characteristics of PL thermal quenching and time decay of prepared Er-doped Si thin films are very similar to those of Er-doped porous Si and/or Er-doped amorphous Si. Furthermore, observation of Er3+ emission from as-prepared thin films without thermal annealing suggests that the Er doping in the form of Er atomic radical species produced by laser ablation is essential in activation of Er3+ ions. Moreover, incorporating a prescribed amount of Er in the bulk target enables us to control the Er doping level in thin films prepared by laser ablation. (C) 1996 American Institute of Physics.
Scientific journal, English

Self limiting growth on nominally oriented (111)A GaAs substrates in atomic layer epitaxy
JS Lee; S Iwai; H Isshiki; T Meguro; T Sugano; Y Aoyagi
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 103, 3, 275-278, Nov. 1996, Peer-reviwed, Layer-by-layer growth on nominally oriented(111)A GaAs substrate has been performed by atomic layer epitaxy (ALE). Under enough AsH3 feeding, the growth rate saturation of one-fourth monolayer per cycle was observed at the T-g range between 560 degrees C and 600 degrees C and three-eighths of monolayer per cycle at the T-g range below 550 degrees C on (111)A substrate. The drastic change of the growth rate saturation at around 550 degrees C indicates some kinds of surface reconstructions or site occupation on (111)A surface during AsH3 supply.
Scientific journal, English

Magnetic field effects in p-type modulation-doped GaAs quantum wires
S Nomura; H Isshiki; Y Aoyagi; T Sugano
PHYSICA B, ELSEVIER SCIENCE BV, 227, 1-4, 38-41, Sep. 1996, Peer-reviwed, Diamagnetic shifts of p-type modulation-doped quantum wires are investigated, Both the heavy- and light-hole-like states are observable in the photoluminescence spectra by heavily doping holes above the light-hole-like state. This allows us the first measurement of the diamagnetic shifts of both the heavy- and light-hole-like states in quantum wires. The observed large diamagnetic shift coefficients are due to asymmetric distribution of the charge densities of an electron and holes in quantum wires.
Scientific journal, English

Atomic layer epitaxy of GaAs and GaAsxP1-x on nominally oriented GaAs(111) substrates with high quality surface and interfaces
JS Lee; S Iwai; H Isshiki; T Meguro; T Sugano; Y Aoyagi
JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, 160, 1-2, 21-26, Mar. 1996, Peer-reviwed, Layer-by-layer growth of GaAs and GaAsxP1-x (x = 0.7-0.8) on nominally oriented (111) substrates has been performed by atomic layer epitaxy (ALE). The ideal growth rate of one monolayer per cycle was obtained on a (111)B substrate, but not on a (111)A substrate, Mirror-like smooth surface morphologies can be obtained on both (111)A and (111)B substrates in a wide range of growth conditions. The X-ray rocking curve of the GaAsxP1-x/GaAs multilayer sample grown on the(lll)B substrate showing clear satellite patterns indicates abrupt interfaces that are superior to those of the (100) sample. It was also found that the disorder in growth such as the generation of hillocks can be reduced drastically by the ALE method.
Scientific journal, English

Characterization of GaAs/GaAsP quantum wire structures fabricated by atomic layer epitaxy
H Isshiki; Y Aoyagi; T Sugano; S Iwai; T Meguro
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 78, 12, 7277-7281, Dec. 1995, We have developed a fabrication process for isolated quantum wire structures, using advanced atomic layer epitaxy (ALE) techniques based on the self-limiting effect. We describe several advantages of the self-limiting effect for the fabrication process of quantum nanostructures. We also present characterizations of the quantum wire structures including photoluminescence (PL) measurements. Due to the fact that the ALE is localized on a nanometer scale and that a growth mode switching technique between isotropic and anisotropic ALE was used, well-defined GaAs quantum wires with structure control were successfully realized. Also, quantum confinement effects of one-dimensional systems have been observed clearly in the quantum wires via PL measurements. (C) 1995 American Institute of Physics.
Scientific journal, English

STEP INDUCED DESORPTION OF ASHX IN ATOMIC LAYER EPITAXY ON GAAS(001) VICINAL SUBSTRATES
JS LEE; S IWAI; H ISSHIKI; T MEGURO; T SUGANO; Y AOYAGI
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 67, 9, 1283-1285, Aug. 1995, Peer-reviwed, We investigate the growth rate of GaAs homoepitaxy on (001) just and vicinal substrates as a function of substrate temperature, feeding rate of source gases, and H-2 purge duration during the atomic layer epitaxy (ALE) process. The desorption of AsHx (x = 0, 1, 2) on vicinal surfaces during ALE was confirmed to be the migration of adsorbed AsHx molecules on the surface and desorption at the steps. (C) 1995 American Institute of Physics.
Scientific journal, English

SURFACE PROCESSES OF SELECTIVE GROWTH BY ATOMIC LAYER EPITAXY
H ISSHIKI; Y AOYAGI; T SUGANO; S IWAI; T MEGURO
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 82-3, 57-63, Dec. 1994, Characteristics and mechanisms, of the crystallographic selective growth by atomic layer epitaxy (ALE) and the localized ALE growth over the nanometer scale area, are discussed focusing on the surface process. The experimental results indicate that higher growth temperature, and longer hydrogen purge time after AsH3 supply, promote the crystallographic selectivity of GaAs ALE growth. The characteristics of the ALE selective growth include high crystallographic selectivity, and high uniformity in the nanometer scale. The mechanisms of ALE selective growth seem to be caused by the separate enhancement of As desorption process and the self-limiting mechanism of Ga precursor adsorption process on the GaAs surface.
Scientific journal, English

RECTANGULAR SHAPED QUANTUM-WIRE FABRICATION BY GROWTH MODE SWITCHING BETWEEN ISOTROPIC AND ANISOTROPIC ATOMIC LAYER EPITAXY
H ISSHIKI; S IWAI; T MEGURO; Y AOYAGI; T SUGANO
JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, 145, 1-4, 976-977, Dec. 1994
Scientific journal, English

Time-resolved study on the impact excitation and quenching processes of the 1.54μm electro luminescence emission of Er ions in InP
T. Kimura; H. Isshiki; H. Ishida; S. Yugo; R. Saito; T.Ikoma
J. Appl. Phys., 76, 3714-3719, Sep. 1994, Peer-reviwed
Scientific journal, English

REDUCTION OF CARBON IMPURITY IN GAAS BY PHOTOIRRADIATION IN ATOMIC LAYER EPITAXY
S IWAI; T MEGURO; H ISSHIKI; T SUGANO; Y AOYAGI
APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 79-80, 232-236, May 1994, Peer-reviwed, GaAs was grown by the atomic layer epitaxy (ALE) technique by means of the alternate supply of trimethylgallium for 1 s and arsine (AsH3) with photo irradiation at 530-degrees-C. The substrate surface was irradiated by an infrared lamp in the first half of the AsH3 feed time. The carrier concentration in the ALE layer grown with irradiation for 4 s at 3 W/cm2 during the 7 s AsH3 feed time was reduced to 9 X 10(15) cm-3, which was one thirtieth as low as that without irradiation. The emission intensity associated with carbon impurity in photo-luminescence spectra decreased with the increase of light intensity.
Scientific journal, English

GAAS CRYSTALLOGRAPHIC SELECTIVE GROWTH BY ATOMIC LAYER EPITAXY AND ITS APPLICATION TO FABRICATION OF QUANTUM-WIRE STRUCTURES
H ISSHIKI; Y AOYAGI; T SUGANO
GALLIUM ARSENIDE AND RELATED COMPOUNDS 1993, IOP PUBLISHING LTD, 136, 136, 643-647, 1994, Peer-reviwed, Crystallographic selective growth using atomic layer epitaxy (ALE) has been developed for the fabrication of low-dimensional quantum structures. In addition, ALE growth mode change between isotropic (side wall) and anisotropic (selective) growth, without growth temperature change, was achieved by control of the hydrogen purge time after AsH3 supply. Due to the self limiting effect and high selectivity of ALE growth, trapezoidal shaped GaAs/(AlAs)(1)(GaAs)(1) quantum wire structures were successfully realized.
Scientific journal, English

CRYSTALLOGRAPHIC SELECTIVE GROWTH OF GAAS BY ATOMIC LAYER EPITAXY
H ISSHIKI; Y AOYAGI; T SUGANO; S IWAI; T MEGURO
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 63, 11, 1528-1530, Sep. 1993, Peer-reviwed, We found high crystallographic selectivity in atomic layer epitaxy (ALE) growth of GaAs, in comparison with other epitaxial growth methods. In the temperature dependence of the GaAs growth rate, no GaAs growth on the GaAs (111) A and (110) planes was observed in the high temperature range under the condition of GaAs ALE growth on GaAs (100) plane. Also we discussed the mechanism of GaAs growth selectivity, which was believed to be caused by growth limitation due to As desorption. Due to the self-limiting effect and the high selectivity of ALE growth, trapezoidal-shaped GaAs/AlGaAs quantum wire structures, with 20 nm thickness and 50 nm width, were successfully realized.
Scientific journal, English

EXCITATION AND RELAXATION PROCESSES OF IMPACT EXCITATION EMISSION OF ER3+ IONS IN INP
T KIMURA; H ISHIDA; S YUGO; R SAITO; H ISSHIKI; T IKOMA
RARE EARTH DOPED SEMICONDUCTORS, MATERIALS RESEARCH SOC, 301, 293-298, 1993, Peer-reviwed
International conference proceedings, English

Formation of low-dimensional structures by atomic layer epitaxy
Journal of Opto-Electronics Devices and Technologies(MITA Press), 8, 509, 1993
Scientific journal, English

Time-resolved study on the impact-excited 1.54 μm emission of Er3+ ions in InP and its excitation and quenching mechanisms
Tadamasa Kimura; Hideo Isshiki; Hiroyuki Ishida; Shigemi Yugo; Riichiro Saito; Toshiaki Ikoma
Conference on Solid State Devices and Materials, Publ by Business Cent for Acad Soc Japan, 246-248, 1992, The EL (electroluminescence) time-decay of the 1.54μm emission of Er3+ doped in InP was investigated between 77K and 330K. The major decay was almost exponential and the decay time showed little thermal quenching, decreasing from 2ms at 77K to 1ms at 330K. This result contrasts with the large thermal quenching of the PL (photo-luminescence) time-decay, suggesting different excited Er3+ centers between EL and PL. The results are analyzed and the excitation and quenching mechanisms are discussed.
International conference proceedings, English

Emission of the 1.54um Er-related peaks by impact excitation of Er atoms in InP and its characteristics
H. Isshiki; H. Kobayashi; S. Yugo; R. Saito; T. Kimura; T. Ikoma
Proc. SPIE, 1361, 223-227, 01 Mar. 1991, Peer-reviwed
International conference proceedings, English

IMPACT EXCITATION OF THE ERBIUM-RELATED 1.54 MU-M LUMINESCENCE PEAK IN ERBIUM-DOPED INP
H ISSHIKI; H KOBAYASHI; S YUGO; T KIMURA; T IKOMA
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 58, 5, 484-486, Feb. 1991, The Er-related 1.54-mu-m luminescence peak has been observed in erbium-doped InP layers by impact excitation of Er atoms with energetic carriers accelerated by electric field. Er ions were implanted into n-type InP and Au/Sn ohmic contacts were formed on top of the surface. The Er-related sharp peak at 1.543-mu-m was observed by only applying dc voltages between the electrodes over the temperature range from 77 to 360 K. Neither band-edge emission nor impurity-related emission were observed, although they were intense in the photoluminescence spectra of the same sample. The fine structure of the 1.54-mu-m peak was also different from that of photoluminescence. This 1.54-mu-m emission was related to erbium atoms excited through collisions with energetic electrons accelerated by the electric field.
Scientific journal, English

1.54 MU-M ELECTROLUMINESCENCE BY ELECTRON-IMPACT EXCITATION OF ER ATOMS DOPED IN INP
H ISSHIKI; H KOBAYASHI; S YUGO; T KIMURA; T IKOMA
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, JAPAN J APPLIED PHYSICS, 30, 2B, L225-L227, Feb. 1991, The Er-related 1.54-mu-m electroluminescence (EL) was observed by impact exciting Er-atoms implanted into InP in the temperature range from 77 K to 360 K. The no shift in the peak wavelength was observed against temperature change. The emission intensity was a slowly decreasing function of temperature, and its room temperature value was still about half the 77 K value. The temperature dependence of the quantum efficiency of the EL emission was discussed in comparison with that of the PL emussion.
Scientific journal, English

Characteristics of the electroluminescence and photoluminescence emission of erbium ions doped in InP and the energy transfer mechanism
Hideo Isshiki; Riichiro Saito; Tadamasa Kimura; Toshiaki Ikoma
Journal of Applied Physics, 70, 11, 6993-6998, 1991, The characteristics of impact excitation of the 1.54-μm emission due to intrashell transitions of 4f electrons of erbium atoms (4I 13/2 →4 I15/2) doped into InP were investigated in comparison with the photoluminescence (PL) emission of the same peak from the same sample. The thermal quenching of this Er-related electroluminescence (EL) emission was found to be very small in contrast to the large thermal quenching of the PL emission. The EL emission intensity at room temperature was half that at 77 K, and the temperature dependence of the emission energy and the spectral width was very small. Due to almost temperature-independent nature of the impact excitation process, the quenching of the EL emission intensity reflected directly that of the fluorescence efficiency of this intrashell transitions of Er 4f electrons. Using this result, the temperature dependence of the PL energy transfer efficiency was also obtained. It was also found that the fine structure of the 1.54-μm emission was different between EL and PL. It was speculated that Er atoms on different lattice sites, which were in different crystal fields, were excited depending on excitation processes.
Scientific journal, English

Study on wave-guiding property of Er_<0.45>Y_<1.55>SiO_5 crystalline waveguide
NAKAJIMA Takayuki; SHINAGAWA Tatsunori; SUGAWARA Takuya; JIANG Yousong; KIMURA Tadamasa; ISSHIKI Hideo
Er_<0.45>Y_<1.55>SiO_5 crystal fabricated by Radical-assisted sputtering showed PL fine structure related to Er_2SiO_5 crystal. And we made Er_<0.45>Y_<1.55>SiO_5 crystalline waveguide and evaluated the wave-guiding property of pumping light at a wavelength of 1480nm. It is estimated the loss coefficient of the waveguide was 174cm^<-1>. Compared with waveguides prepared by sol-gel method previously reported, the loss coefficient of the waveguide made by RAS was 100cm^<-1> smaller than that of ones by sol-gel method. Therefore, we have succeeded in suppressing scattering loss contributed by Er_<0.45>Y_<1.55>SiO_5 crystallite grain., The Institute of Electronics, Information and Communication Engineers, 09 Dec. 2011, Technical report of IEICE. OPE, 111, 358, 23-25, Japanese, 0913-5685, 110009467000, AN10442691

シリコンフォトニクスに向けた新しい発光材料 Er2SiO5超格子結晶
一色 秀夫; 木村 忠正
応用物理学会, May 2009, 応用物理, 78, 5, 427-431, Japanese, Peer-reviwed, Introduction other, 0369-8009, 10024751757, AN00026679

シリコンを光らせるにはどうすればよいのか
木村 忠正; 一色 秀夫
日本工業出版, Jan. 2009, 光アライアンス, 20, 1, 1-7, Japanese, Introduction other, 0917-026X, 40016404635, AA11758790

Fabrication and evaluation of Er_2SiO_5 crystal thin film by spray CVD method
YOSHIZAWA Jun; ISSHIKI Hideo; KIMURA Tadamasa
The Er_2SiO_5 nano-structured crystalline film can be expected to be one of key materials for the silicon photonics. The Er_2SiO_5 crystalline film that fabricated by sol-gel method indicates various properties, but it has a problem that fabricating process is complicated and needs long time for device fabrication. In order to apply Er_2SiO_5 crystalline film to the silicon photonics, we are studying spray CVD (chemical vapor deposition) method that is based on the developed fabrication process using sol-gel method. We adjusted a chemical precursor solution for spray CVD method and examined the spraying parameter. We fabricated Er_2SiO_5 preforms in process chamber consistently, we crystallized the thin film, and then we measured Photoluminescence (PL) and observed Er_2SiO_5 crystalline film formation., The Institute of Electronics, Information and Communication Engineers, 12 Dec. 2008, IEICE technical report, 108, 370, 17-22, Japanese, 0913-5685, 110007115138, AN10442691

ErSiO 超格子結晶 –シリコンフォトニクスに向けた新しい発光材料-
一色 秀夫
Jun. 2006, MRS-J News, 18, 2, 2-3, Japanese, Introduction other

希土類添加半導体の可視発光とLEDの可能性
一色秀夫; 木村忠正
テクノタイムズ社, 2001, Vol.7,No8、pp.18-22(2001), Vol.7, No8, 18-22, Japanese, Introduction other, 1341-3961, 40019857379, AA11422144

理工学のための数学入門 微分方程式・ラプラス変換・フーリエ解析
一色 秀夫; 塩川 高雄
Japanese, Joint work, 第3章ラプラス変換、第4章フーリエ解析、第5章偏微分方程式, vii, 325p, オーム社, Nov. 2020, 9784274226137

電気電子数学入門 微分方程式・ラプラス変換・フーリエ解析
一色 秀夫; 塩川 高雄
Japanese, Joint work, 第3章ラプラス変換、第4章フーリエ解析、第5章偏微分方程式, オーム社, May 2012

Silicon Photonics
Hideo Isshiki
Japanese, Joint work, 第３章 希土類添加シリコン光エミッタ, Ohmsha, Nov. 2007

電子材料ハンドブック
木村忠正; 八百隆文; 奥村徳次; 豊田太郎
Dictionary or encycropedia, Japanese, 朝倉書店, 2007

Conduction Subband Formation in (GaAs)m(GaP)n Fractal struceured Atomic -Layer-Superlattice Grown by Atomic Layer Epitaxy
H. Isshiki; K. Tanaya; T. Kimura; J. S. Lee; Y. Aoyagi; T. Suganoj
English, Preceedings of the 24th lneernational Comference on The physics of Semiconduceors, published by World Scientific Publisshing Co., 1999

Layer-by-layer Synthesis of Functional Oxides by Digitally Processed DC Sputtering with Alternating Surface Oxidation
Hideo Isshiki, Daiki Yamashita, Mehdi Ali, Masaya Takeuchi, Taiga Hokkezu, Yuki Takamatsu, Shoji Kiyota, Satoshi Fujiya and Shinichiro Saisho
Oral presentation, English, 2024 International Conference on Solid State Devices and Materials (SSDM2024), Peer-reviewed
02 Sep. 2024
01 Sep. 2024- 04 Sep. 2024

Room temperature synthesis of ferroelectric Hf1-xZrxO2 films under layer-by-layer approach using digitally processed DC sputtering
Daiki Yamashita; Yuki Takamatsu; Satoshi Fujiya; Koki Takamura; Shinichiro Saisho; Hideo Isshiki
Oral presentation, English, The 17th International Symposium on Sputtering and Plasma Processes(ISSP2024), Peer-reviewed
04 Jul. 2024
02 Jul. 2024- 05 Jul. 2024

Synthesis of CuAlO2/Si heterostructures by DPDS-assisted LBL approach and their transistor characteristics
Mehdi Ali; Daiki Yamashita; Hideo Isshiki
Oral presentation, English, 2023 International Conference on Solid State Device and Materials (SSDM), Peer-reviewed
06 Sep. 2023
05 Sep. 2023- 08 Sep. 2023

Formation of (Er0.1Y0.9)2Zr2O7 waveguide amplifier by digitally processed DC sputtering toward heterogeneous integration on SiNx waveguide circuits
Hideo Isshiki; Yanbin Zhang; Daiki Hashimoto; Satoshi Fujiya; Daiki Yamashita
Oral presentation, English, E-MRS 2023 SPRING MEETING, Peer-reviewed
31 May 2023
29 May 2023- 02 Jun. 2023

Synthesis of functional crystalline oxides by digitally processed DC sputtering synchronized with oxygen gas pulsing
Hideo Isshiki; Koki Takamura; Yanbin Zhang; Daiki Yamashita; Shinnichiro Saisho
Oral presentation, English, E-MRS 2023 SPRING MEETING, Peer-reviewed
30 May 2023
29 May 2023- 02 Jun. 2023

Evaluation of NV0 defects in single-crystal diamonds using Raman spectroscopy
Shohei Yamazaki; Daichi Hagiwara; Takahiro Tsukamoto; Hideo Isshiki
Poster presentation, English, E-MRS 2023 SPRING MEETING, Peer-reviewed
29 May 2023
29 May 2023- 02 Jun. 2023

The Role of Reactive Gas Pulsing Synchronized with Digitally Processed DC Sputtering
Hideo Isshiki; Yasuhito Tanaka; Shinichiro Saisho
Oral presentation, English, The 22nd International Vacuum Congress, Peer-reviewed
14 Sep. 2022
11 Sep. 2022- 16 Sep. 2022

デジタル処理DCスパッタによる機能性酸化物の原子層精度堆積とフォトニクス応用
一色 秀夫; 田中 康仁; 税所 慎一郎
Invited oral presentation, Japanese, 日本表面真空学会、スパッタリングおよびプラズマプロセス技術部会（SP部会）第171回定例研究会, Invited
01 Aug. 2022
01 Aug. 2022- 01 Aug. 2022

デジタル処理 DC スパッタによる光学機能性酸化物の原子層精度堆積
一色 秀夫
Invited oral presentation, Japanese, 電子情報通信学会、第3回光集積及びシリコンフォトニクス(PICS)研究会, Invited
15 Jul. 2022
14 Jul. 2022- 15 Jul. 2022

Atomically Precise Deposition of Multi-Element Metal Oxide Layered Crystals Alternating Digitally Processed DC Sputtering and Surface Oxidation
H. Isshiki; G. Nakamura; G. Fabiola; K. Takamura; M. Ali; Y. Zhang; Y. Tanaka; S. Saisho
Oral presentation, English, 2022 MRS Spring Meeting, Peer-reviewed
10 May 2022
08 May 2022- 13 May 2022

High-Precision Multi-Cathode Pulsed-DC Sputtering Employing Digital Processing
Hideo Isshiki; Tomoki Kasumi; Yasuhito Tanaka; Shinichiro Saisho
Oral presentation, English, the 13th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials / 14th International Conference on Plasma-Nano Technology & Science (ISPlasma2021/IC-PLANTS2021), online conference, International conference
09 Mar. 2021

Layer-by-layer Synthesis of Metal Oxide Compounds by Programable Pulsed-DC Sputtering Combined with Oxygen Pulsed Supply
Hideo Isshiki; Kodai Miyagi; Yasuhito Tanaka; Shinichiro Saisho
Oral presentation, English, 第39回電子材料シンポジウム, オンライン, Domestic conference
07 Oct. 2020

Programmable Radical-Assisted Sputtering Enabling Designed Deposition Processes with Atomic Layer Accuracy
Hideo Isshiki; Yasuhito Tanaka; Shinichiro Saisho
Poster presentation, English, American Vacuum Society (AVS) 66th International Symposium, International conference
25 Oct. 2019

Optical Gain in Mid-Refractive Index Contrast (Er0.1Y0.9)2Zr2O7 /SiO2 Waveguide Prepared by Radical Assisted Sputtering
Kodai Miyagi; Yasuhito Tanaka; Ayuko Minowa; Ghent Nakamura; Hideo Isshiki
Oral presentation, English, Solid State Device and Materials(SSDM) 2019, International conference
05 Sep. 2019

Er silicate waveguide devices for silicon photonics
Hideo Isshiki
Invited oral presentation, English, 2015 International Conference on Optical Instrument and Technology (OIT 2015), Invited, SPIE and China Instrument and Control Society, Biejing, China, http://www.oe-oem.org/oit/, International conference
19 May 2015

蛍光イメージングに向けたナノダイヤモンド中Si-空孔発光中心の形成
一色秀夫
Invited oral presentation, Japanese, 電子情報通信学会 エレクトロニクスソサエティシンポジウム, Invited, 電子情報通信学会 エレクトロニクスソサエティ 量子エレクトロニクス研究専門委員会, 新潟大学, Domestic conference
18 Mar. 2014

Er Silicate Waveguides for Compact Amplifiers and Light Sources on Silicon Platform
Hideo Isshiki
Invited oral presentation, English, International Conference on Group Four Photonics (GFP2013), IEEE, Seoul Korea, International conference
Aug. 2013

Er Silicate Waveguides for On-Chip Optical Amplifiers
Hideo Isshiki
Invited oral presentation, English, CLEO-PR & OECC/PS 2013, CLEO, kyoto, International conference
Jul. 2013

希土類元素を利用したシリコンフォトニクス用発光デバイス
一色 秀夫
Invited oral presentation, Japanese, 第16回シリコンフォトニクス研究会, 電子情報通信学会 エレクトロニクスソサエティ シリコンフォトニクス時限研究専門委員会, 電気通信大学, Domestic conference
25 Nov. 2011

Er silicates system and its application to light source in Si photonics
H. Isshiki
Invited oral presentation, English, JSPS International Schooling on Si photonics 2011, Invited, JSPS Core To Core program, Kyoto, Japan, International conference
16 Nov. 2011

Enhanced Er3+ luminescence by control of energy-migration in ErxY2-xSiO5 crystalline systems
T. Kimura; H. Isshiki
Invited oral presentation, English, E-MRS 2011 Fall Meeting, Symposium : J "Rare earth doped semiconductors and nanostructures for photonics”, Invited, E-MRS, Warsaw, Poland, International conference
18 Sep. 2011

Light sources based on Si and the related materials for silicon photonics
H. Isshiki
Invited oral presentation, English, 15th Opto-Electronics and Communications Conference (OECC 2010), Invited, Opto-Electronics and Communications Conference, Sapporo, Japan, International conference
05 Jul. 2010

ErYSiO超格子結晶の作製とシリコンフォトニクス応用
一色 秀夫; 木村 忠正
Invited oral presentation, Japanese, 未踏・ナノデバイステクノロジー第151委員会 研究会, Invited, 学振 未踏・ナノデバイステクノロジー第151委員会, 東京大学, Domestic conference
29 Jan. 2010

Er2SiO5 compact optical waveguide amplifiers for silicon photonics
Hideo Isshiki; Tadamasa Kimura
Invited oral presentation, English, 1st International Conference on Silicon Photonics, JSPS, Tokyo, International conference
Jan. 2009

Er2SiO5結晶の発光特性と光導波路増幅器への応用
一色秀夫; 牛山智幸; 中島崇之; 王 興軍; 木村忠正
Invited oral presentation, Japanese, 「新世代光通信へのイノベーション」公開シンポジウム, 科研費特定領域研究「新世代光通信へのイノベーション」
Jan. 2009

Fabrication and Evaluation of Self-organized Er2SiO5 Crystalline Films for the 1.5μm Emitters and Amplifiers in Silicon Photonics
T.Kimura; H. Isshiki
Invited oral presentation, English, MRS Fall Meeting, MRS, Boston, International conference
Dec. 2008

Influence of Upconversion on Er2SiO5 Waveguide Light Emitting Devices
Hideo Isshiki; Takayuki Nakajima; Tadamasa Kimura
Public symposium, English, MRS Fall Meeting 2008, MRS, Boston, USA
Dec. 2008

Increase in Excitation Efficiency of Er3+-Related 1.53μm Emission from Er2SiO5 Crystallite Embedded in SRSO
Masaki Oe; Yu Fujiwara; Hideo Isshiki; Tadamasa Kimura
Public symposium, English, MRS Fall Meeting 2009, MRS, Boston, USA
Dec. 2008

Er2SiO5 ナノ構造複合材料の創製とシリコンフォトニクス応用
一色 秀夫
Invited oral presentation, Japanese, マイクロ／ナノフォトニクス部会」第９回研究会, 早稲田大学ナノテクノロジーフォーラム
Nov. 2008

Er2SiO5光導波路型発光デバイスの可能性
一色秀夫; 中山裕介; 大江将巳; 中島崇之; 木村忠正
Invited oral presentation, Japanese, 第10回シリコンフォト二クス研究会, 電子情報通信学会シリコンフォト二クス時限研究専門委員会
Nov. 2008

多結晶ダイヤモンド・コプレーナ三極構造における電界放出・衝突励起発光
神保幸宏; 神山浩輝; 一色秀夫; 木村忠正
Public symposium, Japanese, 第22回ダイヤモンドシンポジウム, ニューダイヤモンドフォーラム, 東京
Oct. 2008

Si上でのﾀﾞｲﾔﾓﾝﾄﾞ深紫外発光素子に向けて-ｴｯﾁﾝｸﾞ加工したSOI基板上へのﾀﾞｲﾔﾓﾝﾄﾞの選択成長-
神山浩輝; 神保幸宏; 一色秀夫; 木村忠正
Public symposium, Japanese, 第22回ダイヤモンドシンポジウム, ニューダイヤモンドフォーラム, 東京
Oct. 2008

MMSiを用いたﾊﾞｲｱｽ法ﾀﾞｲﾔﾓﾝﾄﾞ核発生の検討
吉田樹央; 一色秀夫; 木村忠正
Public symposium, Japanese, 第22回ダイヤモンドシンポジウム, ニューダイヤモンドフォーラム, 東京
Oct. 2008

Structure and Photoluminescence Comparison of Er2SiO5 and Er2O3 Prepared by Sol-Gel Method
X. Wang; H. Isshiki; T. Kimura
Public symposium, English, 5nd International conference of Group IV Photonics, IEEE, Sorrento, Italy
Sep. 2008

Crystalline Structure and Luminescence Properties of Er Silicates Fabricated on Si and SiO2/Si by the Sol-Gel Method
T. Kimura; H. Isshiki
Public symposium, English, 5nd International conference of Group IV Photonics, IEEE, Sorrento, Italy
Sep. 2008

Er2SiO5ナノ結晶の相分離形成と発光特性
一色秀夫
Invited oral presentation, Japanese, 第4回量子ナノ材料セミナー, 量子ナノ材料セミナー運営委員会
Jul. 2008

Investigation of surface-enhanced Raman scattering of diamond related thin films deposited by ring resonator microwave plasma CVD
R. Tobita; H. Isshiki; T. Kimura
Public symposium, Japanese, 27th Electronic Materials Symposium, 電子材料シンポジウム畝委員会, 修善寺
Jul. 2008

Fabrication and evaluation of Er2SiO5 crystalline waveguide
T. Nakajima; T. Ushiyama; H. Isshiki; T. Kimura
Public symposium, Japanese, 27th Electronic Materials Symposium, 電子材料シンポジウム運営委員会, 修善寺
Jul. 2008

Phase separation growth of Er2SiO5 thin film in Si-rich ErSiO preform
H.Isshiki; M.Ohe; T. Samejima; T.Ushiyama; T.Kimura
Public symposium, English, E-MRS Spring meeting 2008, EMRS, Strasburg, France
May 2008

Formation of highly-oriented layer-structured Er2SiO5 films by pulsed laser deposition
Tadamasa Kimura; Yasuhito Tanaka; Hiroshi Ueda; Hideo Isshiki
Public symposium, English, E-MRS Spring meeting 2008, EMRS, Strasburg, France
May 2008

Excitation and luminescence properties of Er2SiO5 crystalline compounds controlled by the sol-gel fabrication process
T.Kimura; H. Isshiki
Invited oral presentation, English, SEDWAL Workshop 2008, Steering comittee of SEDWAL Workshop, Trento, ITALY, International conference
Apr. 2008

Siナノフォトニクス ―次世代LSIにおける電子デバイスと光デバイスとの融合―
木村忠正; 一色秀夫
Invited oral presentation, Japanese, 日本女子大平成19年度先端光情報技術研究会, 日本女子大
Dec. 2007

Er2SiO5結晶の作製と導波路型発光デバイス応用
一色秀夫; 木村忠正
Invited oral presentation, Japanese, 学振第145委員会（結晶加工と評価技術） 第112回研究会, 学振第145委員会
Nov. 2007

シリコンフォトニクスにおける発光源の開発
木村 忠正; 一色 秀夫
Keynote oral presentation, Japanese, 先端半導体ワークショップ, 明治大学, Domestic conference
Oct. 2007

シリコン・フォトニクスにおける発光デバイス
木村忠正; 一色秀夫
Invited oral presentation, Japanese, 第68回応用物理学会学術講演会シンポジウム「シリコン・フォトニクス技術の最新動向」, 応用物理学会
Sep. 2007

ErSiO自己組織化超格子結晶の特性と1.54mm発光素子性能評価
木村忠正; 一色秀夫
Invited oral presentation, Japanese, 光電相互変換第125委員会第196回研究会, 学振第125委員会
May 2007

ErSiO超格子結晶の自己形成と光学特性
一色秀夫
Invited oral presentation, Japanese, 「光・量子場が関わるナノサイエンステクノロジー」研究会, 電気学会コヒーレント量子ビーム技術調査専門委員会
Dec. 2006

ErSiO self-organized superlattice crystal and the possibility of light emitter and amplifier
H. Isshiki; T. Ushiyama; T. Kimura
Invited oral presentation, English, IBEDM2006, Organizing committee of IBEDM, NankiShirahama, JAPAN, International conference
Oct. 2006

ErSiO超格子単結晶新材料の作製、1.54ìm発光特性と高効率LED実現の可能性
木村忠正; 一色秀夫
Invited oral presentation, Japanese, 第53回応用物理学関連連合講演会シンポジウム「シリコン光エミッタ」, 応用物理学会
Mar. 2006

ErSiO Self-Organized Superlattice Crystals as a 1.54µm Luminescent Material
T. Kimura; H. Isshiki
Invited oral presentation, English, LEOS2005, IEEE/LEOS, Sydney, Australia, International conference
Oct. 2005

Self-organized formation of Er-Si-O superlattice
H.Isshiki; T.Kimura; A.Polman
Invited oral presentation, English, MRS Fall Meeting 2004, MRS, Boston, USA, International conference
Nov. 2004

フラクタル構造半導体格子の作製と電子状態制御
一色秀夫
Invited oral presentation, Japanese, 第1回コヒーレント量子ビーム技術交流講演会, 電気学会コヒーレント量子ビーム技術調査専門委員会
Oct. 2003

Er-Si-O自然超格子の形成と光学特性
一色秀夫
Invited oral presentation, Japanese, The 3rd Joint colloquium on Advanced Materials, JCAM実行委員会
Jul. 2003

Electrically excitable Erbium-silicon-oxide nano-complexes by wet chemical synthesis
H.Isshiki; M.J.A. de Dood; T. Kimura; A. Polman
Invited oral presentation, English, MRS Spring Meeting 2003, MRS, San Francisco, USA, International conference
Apr. 2003

Er-O complexes doped in silicon photonic crystals by wet-chemical method and the indirect excitation emissions
H. Isshiki; M.J.A. de Dood; A. Polman; T. Kimura
Oral presentation, English, 2001 MRS Fall meeting
Nov. 2001

Quasi-coherence and electric field effect in Ga(As,P) "fractal" structured lattice
H.Isshiki
Oral presentation, English, 28th International symposium on Compound Semiconductors (ISCS2001)
Oct. 2001

1.5um room temperature emissions from Er-O complexes formed in silicon photonic crystals
H.Isshiki; M.J.A.de Dood; A.Polman; T.Kimura
Oral presentation, English, 20th Electronic Materials Symposium,
Jun. 2001

固相エピタキシー法により作製したErドープSi膜のフォトルミネッセンス及びME-CAICISSによる評価
曾根逸人; 小室修二; 霜田 進; 小林 峰; 一色秀夫; 青野正和
Oral presentation, Japanese, 第48回応用物理学関係連合講演会，明治大学
Mar. 2001

Perfect"fractal"behavior in XPD pattern of Ga（As,P）Fibonacci
H. Isshiki; J. S. Lee; Y. Aoyagi; T. Sugano
Oral presentation, English, The 10th International confference on Metalorganic Vapor Phase Epitaxy（ICMOVPE-X）June 5-9，2000, Sapporo, JAPAN
Jun. 2000

Quasi-Coherency of Electronic States in Ga (As,P) Fractal Structured Lattice
H.Isshiki; T.Kimura; Y.Aoyagi; T.Sugano
Invited oral presentation, English, The Third SANKEN International Symposium "Advanced Nanoelectronics: Devices, Materials, and Computing", March 14-15, 2000, SANKEN, Osaka University, Osaka, Japan, The Third SANKEN International Symposium "Advanced Nanoelectronics: Devices, Materials, and Computing", March 14-15, 2000, SANKEN, Osaka University, Osaka, Japan, International conference
Mar. 2000

Quasi-Coherency of Electronic States in Ga (As,P) Fractal Structured Lattice
H.Isshiki; T.Kimura; Y.Aoyagi; T.Sugano
Invited oral presentation, English, The Third SANKEN International Symposium "Advanced Nanoelectronics: Devices, Materials, and Computing", March 14-15, 2000, SANKEN, Osaka University, Osaka, Japan, International conference
Mar. 2000

先端半導体デバイス基礎
Present
The University of Electro-Communications

電子デバイス
Present
電気通信大学

論理回路学
Present
電気通信大学

先端半導体デバイス基礎
電気通信大学

Current Topics in Fundamental Science and Engineering A
The University of Electro-Communications

学域特別講義A（基盤理工学A）
電気通信大学

応用数学
The University of Electro-Communications

応用数学
電気通信大学

Electronic Devices
The University of Electro-Communications

Logic Circuits
The University of Electro-Communications

American Vacuum Society(AVS)

ニューダイヤモンドフォーラム

電子情報通信学会

応用物理学会

Rare earth doped semiconductors and its application to waveguide active devices for photonic circuits
ISSHIKI Hideo; KIMURA Tadamasa
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), Final goal of this study is to develop optoelpctronic devices and the integration on silicon (Si) for optical fiber communications with WDM technologies. At the first, fabrication process of erbium (Er) doped waveguide for photonic circuits on silicon substrates has been developed. The applications of porous silicon (PS) to make rare earth doped silicon related materials for optoelectronic devices and the integration are expected. The anodic etching process is a main process for PS fabrication, and requires holes in Si. In this study, we propose the modified anodic etching process to form two-dimensional multi-layered nano-PS. Making a back contact on an n-Si substrate as the source of hole supply, the nano-pores grow perpendicular to the substrate surface. Then a hole-blocking layer is formed selectively on the substrate by ion implantation so that nano-PS on selective area can be obtained. Also we have developed an optical activation process of Er ions doped in Si, which is combined rapid oxidation and rapid thermal annealing processes (RTOA). Due to the activation process, thermal quenching of Er related emissions were remarkably reduced so that 1.54 μm intense PL emissions at room temperature were observed. From 2001, we began to study on Er doped Si photonic crystals with Prof. A Polman of FOM-AMOLF in the Netherlands. By using the RTOA process, room temperature 1.54 μm emissions of Er ion doped in Si photonic crystal were observed under electron-hole pair mediated excitations. Furthermore we have found out novel optoelectronic material "ErSiO natural superlattice" under investigation of the RTOA process. The novel material shows fine structure (Stark splitting) of emission and absorption spectra relative to Er ions, intense emission at room temperature and semiconductor nature. On the other hands, metal-organic vapor phase epitaxy (MOVPE) for SiGe is successfully realized for the first time. Ge dot and Si/SiGe superlattice applied to integrated photo detectors were formed on Si substrates by MOVPE., 12650337
2000 - 2001

Dynamics of the Er1.54μm emission of Er-dope SiO_2/Si ultrathin multilayer structures
KIMURA Tadamasa; ISSHIKI Hideo
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), The objectives of this study is to make an Er/SiO_2/Si ultra thin multilayer structure and to measure the energy transfer between carriers in Si and Er as a function of the thickness of the oxide layer which separates carriers and Er, in order to make clear the physical meanings of the effect of the oxide interlayer for the strong Er-related 1.54 μm emission at room temperature and to obtain a design principle for room temperature 1.54 μm luminescent devices. First, the energy transfer from photocarriers generated in Si to Er^<3+> ions is measured from the photoluminescence intensity and fluorescent decay time of the 1.54 μm emission as a function of the thickness of the oxide interlayer. Next, the reduction of the decay time under the cw illumination due to Auger quenching is measured to estimate the energy backtransfer from Er^<3+> ions to photocarriers. It is found that, though both the energy transfer and backtransfer are decreased with increasing the oxide thickness, the latter is decreased much more rapidly. In addition, it is shown that the energy transfer between carriers and Er^<3+> ions is due to the exchange mechanism. In conclusion, a thin oxide layer of 〜 2nm thickness improves the temperature quenching (γ = I_<300K>/I_<20K> = 1/2 〜 1/3 ) and gives the strongest room temperature intensity of the Er-related 1.54 μm luminescence., 12450008
2000 - 2001

低速多価イオンビームによる原子操作
目黒 多加志; 一色 秀夫; 村上 浩一; 尾笹 一成; 青柳 克信
日本学術振興会, 科学研究費助成事業, 理化学研究所, 特定領域研究(B), 高配向性グラファイトに多価のアルゴンイオンを照射することにより、ナノサイズのダイヤモンドの創製が可能なことが、本研究の成果として得られたが、本年度はさらに作成した構造が本来持っていない新たな特性を示すことを明らかにした。高配向性グラファイトに8価のアルゴンイオンを照射した後、He-Cdレーザーを照射しイオン照射領域をsp^3を有するナノダイヤモンド様の構造に変化させ、さらにその構造を水素雰囲気中で600℃、30分間の熱処理を施すことにより、複数の特性に顕著な変化が見られた。グラファイトは可視域、紫外域には発光を示さない材料であるが、20Kで測定したカソードルミネッセンスでは、微弱ながら紫外域に発光を示すことが分かった。また、イオン照射領域に対して走査トンネル顕微鏡を用いて電界放出効果を調べたところ、化学気相成長法で作成した多結晶ダイヤモンド薄膜と同等の電界放出特性を示すことも確認された。これらの結果は、ナノスケールでの新しい材料創製を示唆する結果と考えられる。また、ラマン分光法を用いて多価イオン照射の高配向性グラファイト基板に対する効果を調べた結果、同程度のドーズ量では価数が高くなるにつれて、ディフェクティブなスペクトルが得られた。これは、価数が低い場合には、イオン照射により点欠陥が生成されるが、価数の増加に従い点欠陥の複合体が形成されることを示している。 また、レーザーアブレーションによりナノ構造シリコン(Siナノ微粒子)を創製し、気相での水素表面修飾、および固相でのErとPの不純物をドーピングを試み、Siナノ微粒子の形成過程については第2レーザー照射法により時間分解PL測定を行ない、その動的過程を明らかにし、Erドーピングにより温度消光のないSiナノ結晶の作製とPドナーのSiナノ結晶へのドーピングの可能性を示した。, 11222207
1999 - 2001

半導体量子閉じ込め構造間の電子相互作用による秩序形成と光相互作用に関する共同研究
青柳 克信; BROWN Simon; NEWBURY Ric; 野村 晋太郎; 一色 秀夫
日本学術振興会, 科学研究費助成事業, 理化学研究所, 国際学術研究, 1.試料作製 原子層エピタキシ-法とビームリソグラフィー技術により試料作製を行った。幅が20-30nmの量子細線構造、および、周期150nm幅が25nmチタン/金電極を用いたスプリットゲート法による試料を作製した。これは報告されている試料の中では最小の周期を持つものであり、電子相互作用の観測に適したものと考えられる。 2.測定 輸送現象の測定により閉じ込め構造中の電子密度を測定した。また、強磁場下の光学スペクトルの測定を試料温度を1.9Kから150Kの範囲で行ない、量子閉じ込め構造中の電子密度分布に関する知見を得た。 3.理論解析 実験に使用した試料形状を再現するようなモデル計算をハートレー近似の範囲で行い、電子密度分布を解析した。得られた結果は測定の結果をよく再現した。, 09044112
1997 - 1997

Optical Memory Fabricated by Rare Earths-Doped Si Nanostructures
ZHAO Xinwie; ISSIKI Hideo
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The Institute of Physical and Chemical Research (RIKEN), Grant-in-Aid for Scientific Research (C), Er ions doped in Si nanometer-sized materials give rise to intense 1.54mum emission at room temperature. The motivation of this study is to apply the Er-doped nanocrystalline Si to new optical devices and memories. Main results of this project are shown in bellow. (1).Size control of Si nanocrystallites by using Eras a nucleation center Size control of Si nanocrystallites formed in n-Si matrix is achieved by using Er as a nucleation center. We have fabricated a series of nc-Si samples with size from 3 nm to 10 am. The smallest crystallite size was 2.7 nm. a Si dot including -1000 atoms. The nc-Si layers are homogeneous both in the crystallite size and in the optoelectronic properties. The samples show a blue emission band and a sharp peak at 1.54mum up to room temperature. We showed that the blue emission shift to higher energies with decreasing size which is in good agreement with the absorption data and could be explained by a novel quantum size effect. (2).Room-temperature 1.54 mum emission from Er-doped porous Si Er was doped into porous Si by immersing the porous Si sample in a saturated ErCl_3 : ethanol solution. Sharp and intense 1.54 mum photoluminescence caused by intra-4f-shell transitions in Er^<3+> ions was observed up to room temperature. Time resolved study of the Er-doped porous Si revealed that the doped Er^<3+> ions were excited by energy transfer from electron-hole pairs in the host. The energy back transfer process is not a dominant factor to quench the Er-related emission in porous Si. A probe effect of measuring the absorption edge of the host by Er emission was proved both for porous Si and nc-Si. Our results were well explained by a proposed model in which an intermediate state was introduced. (3).An Er-doped nc-Si laser operated at room temperature Er-doped nc-Si waveguides were fabricated on Si substrates. A stimulated emission at 1.54 mum was demonstrated at room temperature. The sizes of the fabricated Er-doped nc-Si waveguides were 5000 nm x 200 nm x L, where L is the cavity length and is changed from 1 mm to 10 mm. This is the first breakthrough of realizing an all-Si laser., 08650415
1996 - 1997

Periodic Modulation of Superlattice by Atomic Layer Epitaxy and Its Application to synthesis of Novel Functional Materials
IWAI Sohachi; MEGURO Takashi; ISSHIKI Hideo; AOYAGI Yoshinobu
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The Institute of Physical and Chemical research (RIKEN), Grant-in-Aid for Scientific Research (B), Electronic states in usual periodic structures are given by the periodicity like Bloch theorem. Introducing non-periodicity into the lattice, the electronic states with singular coherency of electron wavefunctions can be expected. We have focused on the periodic modulation (Fractal etc.) of lattice, and carried on the fablication and the characterization of periodic-modulated superlattices, as novel functional materials. The results of this study are summarized as follows. (1)Development of atomic-layer manipulation technologies for superlattice : (GaAs)m(GaP)n and (AIP)m(GaP)n atomic-layer superlattices have been successfully realized by atomic layer epitaxy(ALE), and also the inter-diffusion between the mono-layer lattice has been discussed. (2)Periodic modulation of superlattice with atomic-layer accuracy : GaAs/GaP and AlP/GaP periodic-modulated superlattices have been successfully realized with atomic-layer accuracy by the ALE technologies. Periodic, quasi-periodic (Fractal), random, and multi-periodic structures have been used as the modulated structures, and especially Fibonacci progression has been used as Fractal structures. (3)X-ray analysis of the periodic-modulated superlattices : The XRD pattern of quasi-periodic superlattice shows no periodicity but self-similar geometry, and is consistent with the FFT spectrum of a Fractal structure. Also the X-ray reflection measurement of multi-periodic superlattice shows that the reflection wavelength can be controlled with sub-monolayer accuracy by modulation of the periodicity. This suggests the possibility of application to X-ray mirrors. (4)Optical characterization of electronic states in the periodic-modulated superlattices : Photo-reflectance spectrum of quasi-periodic, random superlattices show peculiar splitting of the subband (electronic states) in comparison with that of the periodic lattice, and are consistent with a transfer matrix calculation for the lattices. This result suggests that the control of electronic state can be possible artificially due to the periodic modulation using the ALE technologies. (5)Application to X-ray mirrors : We have discussed the application of periodic modulation for the lattice to X-ray mirror. Introducing the multiple period into atomic layer superlattice, the reflection wavelength can be controlled arbitrary with sub-monolayer accuracy that is needed to X-ray mirrors., 08455154
1996 - 1997

Fabrication and Characterization of Atomic Layr Controlled Quantum Nano-structures
IWAI Sohachi; MEGURO Takashi; ISSHIKI Hideo; AOYAGI Yoshinobu
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The Institute of Physical and Chemical research (RIKEN), Grant-in-Aid for General Scientific Research (B), Advanced technologies of controlling low-dimensional quantum structures (i.e.size, shape, composition, arrangement and doping control) with atomic-level accuracy were developed, based on atomic layr epitaxy (ALE) selective gwowth, for the future quantum devuces. The results o this study are summarized as follows. (1) Growth mechanism of localized-ALE in nano-space, and layr-by-layr growth mode switching technique It has been found that ALE selective growth makes the control of semiconductor structures possible even in nanometer scale area (Localized-ALE), which is due to the self-limiting effect. Also layr-by-layr growth mode switching technique between anisotropic and isotropic ALE growth, using control of the growth sequence, was developed with the concept as a "selective-control of surface-processes". (2) Development of fabrication processes of low-dimensional quantum structures using ALE growth mode switching technique Fabrication processes of low-dimensional quantum structures were developed, and rectangular shaped quantum wire structures were successfully realized. In this study, the fabrication of low dimensional atomic layr short-period superlattice by using the advanced ALE techniques were demonstrated, for the control of "conposition" and "arrangement" in quantum nano-structures. (3)Development of Digital-etching : Control of surface reaction by tunable UN laser Digital-etching of GaAs using tunable UV laser was discussed. It was found that alternative procedures between feed the enchant (Cl_2) and laser beam irradiation with precious wavelength is necessary to realize the self-limiting effect in digital etching process. (4) Observation and analysis of quantum size effects in low-dimensional quantum structures. Photoluminescence (PL) measurements on GaAs/GaAsP rectangular shaped quantum wires have been performed. One dimensional (1D) confinement effect on the structures has been confirmed by the PL emission and the polarization dependence of the PL spectra. Also the particular electronic states on valence band in the wires, whhich is due to the band mixing effect, was observed by the PL emission from the p-type modulation doped wire structures. Diamagnetic shift of PL emission from the wires also observed., 06452224
1994 - 1995

原子層エピタキシ-による原子層制御新物質の創製
一色 秀夫
日本学術振興会, 科学研究費助成事業, 理化学研究所, 奨励研究(A), 原子層成長(ALE)を用いた低次元量子構造作製プロセス開発を目的としてALE選択成長機構解明に重点を置き,ALE技術の潜在能力を引き出し新たなプロセス技術を開発した。更にALE選択成長により作製した微細量子構造の基礎的な光物性評価を行い明確な一次元閉じ込め効果を観測した。本年度の成果は以下のとおりである。 (1)成長モード切り替え技術の開発、極微細領域中の局財ALE成長の機構解明 ALEにおける面方位選択成長機構を解明した。この結果、成長シーケンスによりALE成長中の表面反応の選択的な制御が可能であることを見出し、ALE成長モード切り替え(isotropic〈-〉anisotropic)技術を確立した。さらに低次元量子構造を作製するうえで重要となる極微細領域における成長速度の変動についても検討を行った。そしてALEの特徴である自己停止機構によりナノメートルエリアにおいても異常成長がなく原子層制御可能な局在ALE成長が可能であることを示した。 ALE成長モード切り替え技術を用いた低次元量子構造作製プロセスの開発 上記の結果をもとに、さらに赤外光照射効果によるALE成長中における炭素原子混入の低減化を組み見合わせて、構造及び組成の原子層制御が可能である低次元量子構造作製プロセスを開発し、矩形量子細線の作製に成功した。 (3)低次元構造における量子サイズ効果の観測、解析 ALE選択成長により作製した矩形量子細線からのフォトルミネッセンス(PL)発光を観測し、そのPLスペクトル及び偏光依存性(光学的異方性)から一次元閉じ込め効果を観測した。また、量子細線構造特有の価電子帯における電子状態の観測に成功した。, 06750338
1994 - 1994

原子層エピタキシ-選択成長による低次元量子構造作製に関する研究
岩井 荘八; 目黒 多加志; 青柳 克信; 一色 秀夫
日本学術振興会, 科学研究費助成事業, 理化学研究所, 重点領域研究, 本年度は原子層成長(ALE)を用いた低次元量子構造作製プロセス開発を目的としてALE選択成長機構解明に重点を置き、ALE技術の潜在能力を引き出し新たなプロセス技術を開発した。更にALE選択成長により作製した微細量子構造の基礎的な光物性評価を行い明確な一次元閉じ込め効果を観測した。本年度の成果は以下のとおりである。 (1)成長モード切り替え技術の開発、極微細領域中の局在ALE成長の機構解明 ALEにおける面方位選択成長機構を解明した。この結果、成長シーケンスによりALE成長中の表面反応の選択的な制御が可能であることを見出し、ALE成長モード切り替え(isotropic〈-〉anisotropic)技術を確立した。さらに低次元量子構造を作製するうえで重要となる極微細領域における成長速度の変動についても検討を行った。そしてALEの特徴である自己停止機構によりナノメートルエリアにおいても異常成長のない均一な局在ALE成長が可能であることを示した。 (2)ALE成長薄膜の結晶性向上 結晶成長中における炭素原子混入の低減について検討を行った結果、GaAsALE成長において赤外光照射が有効であることを示した。 (3)ALE成長モード切り替え技術を用いた低次元量子構造作製プロセスの開発 上記(1),(2)の結果をもとにALEを用いた低次元量子構造の作製プロセスを開発し、矩形量子細線の作製に成功した。 (4)低次元量子構造における量子サイズ効果の観測、解析 ALE選択成長により作製した矩形量子細線からのフォトルミネッセンス(PL)発光を観測し、そのPLスペクトル及び偏光依存性から一次元閉じ込め効果を観測した。また、量子細線構造特有の価電子帯における電子状態の観測に成功した。, 06238219
1994 - 1994

ナノ結晶ダイヤモンド及びその製造方法、製造装置
Patent right, 一色 秀夫, PCT JP2016 77641, Date applied: 20 Sep. 2016

単結晶ダイヤモンドの製造方法、単結晶ダイヤモンド、単結晶ダイヤモンド基板の製造方法、単結晶ダイヤモンド基板及び半導体デバイス
Patent right, 一色 秀夫, 相馬 勇治, 小宮 一輝, 小島 隆平, 特願2014-175926, Date applied: 2014

原子層成長による薄膜形成方法
Patent right, 一色秀夫, 岩井荘八, 青柳克信, 菅野卓雄, 特願2002-187362, Date applied: 27 Jun. 2002, 2003-051450, Date announced: 21 Feb. 2003, 3668802, Date issued: 22 Apr. 2005

ダイヤモンド薄膜のコーティング法及びダイヤモンド被膜超硬合金部材
Patent right, 一色秀夫, 特願2004-173078, Date applied: 10 Jun. 2004, WO2005/121398, Date announced: 2005

原子層成長による量子細線および量子箱の形成方法
Patent right, 一色秀夫, 岩井荘八, 青柳克信, 菅野卓雄, 特願平4-243711, Date applied: 11 Sep. 1992, H06-097071, Date announced: 08 Apr. 1994, 3335671, Date issued: 02 Aug. 2002

レーザーおよびその製造方法
Patent right, 趙新為, 小室修二, 一色秀夫, 青柳克信, 菅野卓雄, 特願平10-372032, Date applied: 28 Dec. 1998, 2000-196191, Date announced: 14 Jul. 2000, 3076019, Date issued: 09 Jun. 2000

微小トンネル接合の形成方法及び微小トンネル接合素子
Patent right, 一色秀夫, 青柳克信, 菅野卓雄, 特願平8-158078, Date applied: 19 Jun. 1996

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