Photo-induced Current and Degradation in Al4C3/Al2O3 (0001) Grown by Metalorganic Chemical Vapor Deposition


Fabrication of C-Doped p-AlGaInN Light-Emitting Diodes by the Insertion of Al4C3


Electroluminescence orientation in InGaN/GaN LED on nano-patterned sapphire by MOCVD

Journal of Wuhan University of Technology. Materials Science Edition


GaN-based light emitting diodes with periodic nano-structures on the surface fabricated by nanoimprint lithography technique

Physica Status Solidi (C) Current Topics in Solid State Physics


Evaluation and re-growth of p-GaN on nano-patterned GaN on sapphire substrate


GaN surface nanostructure photodetector based on back side incidence


Fabrication and Photovoltaic Measurements of Surface Nanostructure of AlGaInN-Based Photodetector

The photovoltage from a surface nanostructure photodetector was measured at wavelengths of 410 and 388 nm as a function of incident angle. Nanostructure devices were fabricated from the wafer with the light-emitting diode (LED) structure grown by metal organic chemical vapor deposition (MOCVD). A nanopattern was successfully fabricated on the surface of the wafer by a nanoimprint lithography technique. The nanopattern was designed as regular triangles consisting of columns, whose diameter and period were 150 and 300 nm, respectively. The photovoltage between the p- and n-layers of the surface nanostructure photodetector showed 6 or 12 periods when the incident illumination angle was changed. The photovoltage minimums were obtained at 30° off of the direction $(10ar{1}0)$ of GaN at large incident angle, and this corresponded well to the experimental results obtained from the LED with the same nanopattern.

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


AlGaN epitaxial lateral overgrowth on Ti-evaporated GaN/sapphire substrate


GaN- and AlGaN-based UV-LEDs on Sapphire by Metalorganic Chemical Vapor Deposition


Blue light emitting diode fabricated on a-plane GaN film over r-sapphire substrate and on a-plane bulk GaN substrate


Growth of AlN and GaN by metalorganic chemical vapor deposition on BP synthesized by flux method

BP with the size of 50 μm to 3 mm was synthesized by the Cu flux method. The BP crystals have a zincblend structure, and the lattice constant and the cathodoluminescence peak wavelength were 4.557 Å and 370 nm, respectively. GaN and AlN were grown by metalorganic chemical vapor deposition on BP. It was found that AlN grown at 1150 °C on (100)BP was grown smoothly but that grown on (111)BP had a rough surface. GaN, however, was irregularly grown on both (100) and (111)BP. It was demonstrated that AlN on (100)BP is another candidate as a substrate for a UV-light-emitting diode.

Japanese Journal of Applied Physics, Part 2 (Letters)


Effect of middletemperature intermediate layer on crystal quality of AlGaN grown on sapphire substrates by metal organic chemical vapor deposition


Al0.17Ga0.83N Film Using Middle-Temperature Intermediate Layer Grown on (0001) Sapphire Substrate by Metal-Organic Chemical Vapor Deposition

The reduction of the dislocation density in a high-temperature (HT)-Al0.17Ga0.83N epitaxial layer was achieved by a middle-temperature (MT)-intermediate layer technique, in which the HT and the MT were 1050 and 950 °C, respectively. For one set of the MT-intermediate layer, the structure was 4.5-μm-thick HT-Al0.17Ga0.83N/1-μm-thick MT-intermediate layer/100-nm-thick HT-Al0.17Ga0.83N layer/low-temperature (LT)-GaNP buffer/trenched (0001) sapphire. The full-width at half maximum values of (0002) and ($10ar{1}2$) diffraction peaks of the X-ray diffraction for the Al0.17Ga0.83N epitaxial layer using one set of the MT-intermediate layer were improved to 359 and 486 arcsec compared with 401 and 977 arcsec for the film without the MT-intermediate layer technique, respectively. Transmission electron microscopy result showed that the dislocation density in the Al0.17Ga0.83N film using one set of MT-intermediate layer was reduced from $(1--4)imes 10^{10}$ to $1.7imes 10^{9}$ cm-2. The Al0.17Ga0.83N epitaxial film including two sets of MT-intermediate layers improved the most, showing a dislocation density of $9.3imes 10^{8}$ cm-2.


Al0.17Ga0.83N film with Middle Temperature Intermediate Layer Grown on Trenched Sapphire Substrate by MOCVD


Growth of thich a-plane GaN on r-plane sapphire by direct synthesis method

Physica Status Solidi (C) Current Topics in Solid State Physics


Inversion domain in AlGaN films grown on patterned sapphire substrate


Diffusion effect-induced InNAs films growth on GaAs(100) substrates by MOCVD


Effect of GaNP Buffer Layer on AlGaN Epilayers Deposited on (0001) Sapphire Substrates by Metalorganic Chemical Vapor Deposition

AlxGa1-xN ($x eq 0.1$) epilayers grown on (0001) sapphire substrates by low-pressure metalorganic chemical vapor deposition with low-temperature (LT)-GaNP buffer have been characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the full width at half maximum (FWHM) values of the GaNP-buffer-based AlxGa1-xN ($x eq 0.1$) epilayers decrease are lower than that of the conventional GaN-buffer-based AlxGa1-xN ($x eq 0.1$) epilayers, but the difference becomes smaller as the Al composition increases. These results could be mainly attributed to a longer diffusion length with the GaNP buffer layer than with the GaN buffer layer.


Interdiffusion induced In(Ga)NAs films growth on GaAs substrates by low-pressure metalorganic chemical vapor deposition


Effects of V/III flux ratio on AlInGaN/AlGaN quantum wells grown by atmospheric pressure MOCVD


Surface smoothing mechanism of AlN film by initially alternating supply of ammonia

A buffer technique that initially alternates supply of ammonia (IASA) is employed for AlN film growth on sapphire substrate by metalorganic chemical vapor deposition (MOCVD). Atomic force microscopy (AFM) study reveals that step-flow-like growth morphology is achieved for the AlN film with the root-mean-square (rms) roughness as small as 0.336 nm. In contrast, the surface morphology of thick AlN film grown directly on sapphire substrate shows rough grainy feature with a large rms value of 28.9 nm. The mechanism leading to superior morphology by introducing IASA process is investigated using transmission electron microscopy (TEM), hot wet chemical etching and scanning electron microscopy (SEM) techniques. Evidence is presented that their morphological differences are attributed to strain reduction and polarity inversion. The present work provides insight into the AlN epitaxial growth and indicates that IASA is an effective method to realize atomically smooth AlN film.


Influence of undoped GaN layer thickness to the performance of AlGaN/GaN-based ultraviolet light-emitting diodes

GaN の転位が厚さに依存すること，および厚さが0.5 um のときは0であることを見出した．とくにAlGaN の層が3次元の山の上に立っているときには，AlGaN 中の歪がゼロであることをみいだしている．


Investigations of V-shaped Defects and Photoluminescence of Thin GaN-Rich GaNP Layers Grown on a GaN Epilayer by Metalorganic Chemical Vapor Deposition

GaNでは珍しいGaPNを歪超格子に用いている．GaPNは圧縮歪を受け，V型溝を形成する．


The Influence of a Low Temperature GaNP Buffer on GaN Growth by Metalorganic Chemical Vapor Deposition

サファイヤ上に，普通は低音成長AlN かGaN を使うところにGaPNを用いた．GaPNは核発生しにくく飛び飛びの核しか形成しない．これで大型のGaN膜が形成できるようになった．


Growth and evaluation of GaN with SiN Interlayer by MOCVD

MOCVD法においてSiN中間層を用いたGaN膜の低転位化手法について検討した,TEM実験により,中間SiN層で転位が終端することを示し,そのメカニズムを議論した.

Physica Status Solidi (C) Current Topics in Solid State Physics


Cracks and dislocation structures in AlGaN systems

We have performed a complex study of the dislocation/crack distribution in the misfit-strained AlGaN/GaN systems. Two different samples were analysed without and with top GaN overlayer. The co-existence of the optically visible dominant cracks with the AlGaN-GaN interface-related subdominant crack system is reported. The structure of the subdominant crack network is analysed; strong correlation between subdominant cracks and the interface-related edge dislocations is revealed.

AlGaNをGaN の上につける問題の1つは，クラックである．これを避けるための手段を開発した．


Space charge effects, carrier capture transient behaviour and α particle detection in semi-insulating GaN

半絶縁性のGaN 基板が，スペースチャージの電荷の計測に重要であることを示している．

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment


High Efficiency GaN-Based LEDs using Plasma Selective Treatment of p-GaN Surface

GaNベースの発光ダイオードでp型の表面層をどうするかで中身は変わってくる．P型を少し削って透明電極をつけると20%出力が増加する．

Physica Status Solidi (A) Applications and Materials Science


Semi-insulating GaN and Its Evaluation for α Particle Detection

半絶縁性のGaNが粒子の検出に役に立つ．とくに高エネルギー粒子の場合は飛びぬけている．


Dislocation Reduction in GaN Layer by Introducing GaN-rich GaNP Intermediate Layers

低温成長のGaNPにつぃてその詳細を発表した．

低温成長のGaNPにつぃてその詳細を発表した．

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Growth of InAs on GaAs(100) by Low-Pressure Metalorganic Chemical Vapor Deposition Employing in situ Generated Arsine Radicals

イン·シツで発生したアルシンとTMGを用いたGaをベースにInAs を成長した．


GaN growth using a low-temperature GaNP buffer on sapphire by metalorganic chemical vapor deposition

低温成長GaNPのTEMを始めて示した．この結果，転位密度が1/4になっていることがわかった．


Interaction Between Inversion Domains and InGaN/GaN Multiple Quantum Wells Investigated by Transmission Electron Microscopy

インバージョンドメインとInGaN/GaN MQWとの相関について議論した．

インバージョンドメインとInGaN/GaN MQWとの相関について議論した．


Monolithic Blue LED Series Arrays for High-Voltage AC Operation

交流ACで光らせるためのLEDを開発した．直列·並列接続で直流電流成分は増える．それに直列抵抗を加えることでAC 100Vで動くようになった．

Physica Status Solidi (A) Applied Research


Dislocation reduction in GaN epilayers grown on a GaNP buffer on sapphire substrate by metalorganic chemical vapor deposition

Dislocation defects in a GaN epilayer grown on a low-temperature GaN-rich GaNP (LT-GaNP) buffer on sapphire substrate by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) were investigated by means of transmission electron microscopy and atomic force microscopy. The GaNP-buffer-based high-temperature GaN (HT-GaN) layers have a dislocation density as low as 5×10^8 cm^<-2>, which can be compared to the best results for GaN epilayers grown on sapphire by atmospheric pressure MOCVD using the conventional LT-GaN or -AlN buffer. The dislocation density reduction could be predominately attributed to an enhanced lateral overgrowth for the HT-GaN layer grown on a GaNP buffer, which is confirmed by the observation of a special morphology evolution beginning from the GaNP buffer.

成長したGaNPへの転位の動向についてしらべた．その結果，転位は減ることが確認された．

Japanese Journal of Applied Physics, Part 2 (Letters)


Influence of pyramidal defects on photoluminescence of Mg-doped AlGaN/GaN superlattice structures

Mg をドープした結晶によく現れるピラミッド型の欠陥に対してAlGaN/GaN のPLへの影響を調べた．


Fabrication of high-output-power AlGaN/GaN-based UV-light-emitting diode using a Ga droplet layer

GaドロップレットをはさみこみLEDの効率が改善した．Gaにより，その回りが歪みがあるようである．その歪みにより効率が改善する．


High-Performance 348nm AlGaN/GaN-based ultraviolet-light-emitting diode with a SiN buffer layer

SiNつきで348 nmで明るく光るLEDを開発した．SiNによりGaN中の転位が減るので明るく光る．

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Characterization of Metal/GaN Shottky Interfaces Based on I-V-T Characteristics

GaN MIS構造を作るために書いた論文である．

GaN MIS構造を作るために書いた論文である．


ICTS measurements for p-GaN Schottky contacts


Bulk GaN growth by direct synthesis method

直接合成法によるバルクGaNの結晶成長を行った．サファイア基板上にMOCVD法により薄膜GaNを成長したものを基板に用いると平坦な表面の厚膜GaNが得られた．サファイア上に直接成長を行うと表面は荒れ結晶性の良くないGaNが成長したが，直接合成法でもバッファ層を導入することにより表面が平坦で結晶性の良い厚膜GaNを成長することに成功した．


金属/p-GaN 電極界面の電流輸送機構の理解

金属/p-GaN 電極界面の電流輸送機構の理解


The development of a novel three-flow six-wafer reactor of metal-organic chemical vapor deposition system for GaN-based structure

2インチ6枚機の仕様を持ったMOCVD機を作った．AlGaN ですべての組成を持つ混晶がえられた．


Fabrication of high performance of AlGaN/GaN-based UV light-emitting diodes

明るく発光するAlGaN/GaN系のLEDを作った．品質の上回るAlGaN/GaN を作ることが重要である．


Phonon and Photon Emission from Optically Excited InGaN/GaN Multiple Quantum Wells

Physica Status Solidi (B) Basic Solid State Physics : PSS


Photoluminescence study on InGaN/GaN quantum-well structure grown on (11-20) sapphire substrate


Characterization of GaN Films etched using reactive ion etching technique by secondary ion mass spectrometry

2次イオン質量分析法を用い,反応性イオンエッチング法によりエッチングされたGaN膜を評価した.残留ボロンが電気特性大きな影響を与え,Clによる表面改質がデバイス特性改善に有効であることを示した.

Materials Science in Semiconductor Processing


Influence of carrier gas on the morphology and structure of GaN layers grown on sapphire substrate by six-wafer metal organic chemical vapor deposition system


(0001) oriented GaN epilayer grown on (11-20) sapphire by MOCVD


Phase giagram for the quantum Hall effect in a high-mobility AlGaN/GaN heterostructure


Study of the strain relaxation in InGaN/GaN multiple quantum well atructures


Growth of InNAs by low-pressure metalorganic chemical vapor deposition employing microwave-cracked nitrogen and in situ generated arsine radicals

減圧MOCVD成長によりInNAsをGaAs基板上にした．プラズマにより発生したアルシンラジカルを使用して，初めて成長に成功した．


Investigation of the strain-relaxation in InGaN/GaN multiple-quantum-well structures


A Study of dislocations in InGaN/GaN multiple-quantum-well structure grownon (11-20) sapphire substrate


Relationship between classical and quantum lifetimes in AlGaN/GaN heterostructures


Cracking of GaN on sapphire from etch-process-induced nonuniformity in residual thermal stress


Influence of InGaN/GaN quantum-well structure on the performance of light-emitting diodes and laser diodes grown on sapphire substrate


Modulation-doping influence on the photoluminescence from the two-dimensional electron gas of AlGaN/GaN heterostructures

Physical Review B, Condensed Matter and Materials Physics


A New Method of Reducing Dislocation Density in GaN Layer Grown on Sapphire Substrate by MOVPE

SiNバッファ層を用いた低転位GaN膜成長方法について議論し，その低転位化機構をAFM，X線回折を用いて調査し，結晶成長モデルを提案した．


Large Schottky Barriers and Memory Capability for Ni Contacts Formed on Low Mg-Doped p-GaN


Electronic Structures of GaNP and InNAs Ordered Alloys Calculated by the Pseudopotential Method


Indium silicon co-doping in AlGaN/GaN multiple quantum wells


The Influence of the Low-Temperature Buffer-Layer on Substrate-Induced Biaxial Compressive Stress in a GaN Film on a Sapphire Substrate


Influence of Inhomogeneous Barrier on I-V Characteristics of Metal/GaN Schottky Diode


The Investigation on the Emission Mechanism of InGaN/GaN Quantum Well Structure


Comparison of the Optical Properties in InGaN/GaN Quantum Well Structures Grown on (0001) and (11-20) Sapphire Substrates


Cracking of GaN on Sapphire from Induced Non-Uniformity in Residual Stress


In-Situ Etch-Layer Monitoring of GaN Based Laser Diode Structure


Photoluminescence Properties of Eu-doped GaN by Ion Implantation


Photoluminescence Studies of InGaN/GaN Multi-Quantum wellsstructuresSubstrates


Influence of the quantum-well thickness on the radiative recombination of InGaN/GaN quantum well structuresSubstrates


X-ray studies of group III-nitride quantum wells with high quality interfaces

Journal of Vacuum Science & Technology B


Reactive ion etching of GaN using BCl3,BCl3/Ar and BCl3/N2 gas plasmas


Role of dislocation in InGaN/GaN quantum wells grown on bulk GaN and sapphire substrates

Dislocation properties in InGaN/GaN Quantum Wells and GaN grown on bulk GaN and sapphire substrates by metalorganic chemical vapor deposition (MOCVD) were characterized using cathodoluminescnece (CL), transmission electron microscopy (TEM), atomic force microscopy (AFM) and photoluminescence (PL). It was clearly demonstrated that dislocations act as nonradiative recombination centers in both n-type (undoped and Si-doped) GaN and InGaN layers. Furthermore the very short-minority carrier diffusion length was a key parameter to explain the high light emission efficiency in GaN-based light emitting diodes (LEDs) prepared on sapphire substrates. On the other side band-tail states were detected in the heteroepitaxial InGaN layers only by temperature dependence PL measurement. Additionally InGaN phase separation, which consists of few micron domains, has been produced under growth conditions which favors the spiral growth. These results indicate that the dislocations in the InGaN layers act as triggering centers for the InGaN phase separation which cause both a compositional fluctuation and the formation of few micron phase separated domains. The homoepitaxial InGaN layers showed however quite normal behaviors for all characterizations.


Optical properties of bound excitons and biexcitons in GaN

Excitonic optical properties of GaN homoepitaxial layers have been studied by means of magneto-luminescence and time-resolved luminescence spectroscopy. The luminescence lines due to the radiative recombination of excitons bound to neutral donors and acceptors have been measured under magnetic field up to 8T, which was aligned perpendicular and parallel to the hexagonal c-axis. Under the magnetic field aligned perpendicular to the hexagonal c-axis, both the donor- and acceptor-bound-exciton lines clearly split into two components, which originated from the Zeeman splitting. The effective g-factors for both the donor- and acceptor-bound excitons were estimated to be 2.02 and 2.47, respectively. Under the magnetic field aligned parallel to the hexagonal c-axis, slight broadening of the bound-exciton lines was observed and the Zeeman splitting was too small to be detected. On the other hand, the diamagnetic shift for both the donor- and acceptor-bound-exciton luminescence lines was observed under the magnetic field aligned both perpendicular and parallel to the hexagonal c-axis. It was found that the diamagnetic shift of the donor-bound exciton was smaller than that of the acceptor-bound exciton. Furthermore, recombination dynamics of excitonic transitions was measured under high-density excitation. An excitation-density-dependent transition of the dominant radiative recombination process from donor-bound excitons to biexcitons was clearly observed in the temporal behavior. In addition, double-exponential decay of biexciton luminescence was observed, which is one of the characteristics of biexciton luminescence at high excitation densities.


Selective fabrication of InGaN nanostructures by the focused ion beam/metalorganic chemical vapor deposition process

サファイア基板上に成長したGaNをSIでコートし，部分的にFIBで窓を開けることにより選択的にInGaNナノ構造を作製した．ナノ構造はMOCVD法により作製したが，窓を開けた部分にのみInGaN/GaNが成長し，その先端部分に量子細線もしくは量子ドットが形成されていることをSEMやCLによって確認した．


Annealing of GaN-InGaN MQW: Correlation between the Bandgap and Yellow Photoluminescence

GaN-InGaN のMQW構造をMOCVD法を用いて作製し，そのバンドギャップ，および黄色波長域のフォトルミネッセンスのアニーリング温度依存性を明らかにした．

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Homoepitaxial and Heteroepitaxial Growth of InGaN/GaN

Electronics and Communications in Japan(Part II:Electronics)


Characterization of RIE etched surface of GaN using methane gas with chlorine plasma


Band-tail model and temperature-induced blue-shift in photoluminescence spectra of InxGa1-xN grown on sapphire


Heteroepitaxial growth of InAs by low-pressure metalorganic chemical vapor deposition employing in situ generated arsine radicals


Growth of GaN layer by metallorganic vapor deposition system with a novel three-flow reactor


The formation of In-rich regions at the perphery of the inverted hexahonalpits of InGaN thin-films grown by metalorganic vapor phase epitaxy

MRS INTERNET JOURNAL OF NITRIDE SEMICONDUCTOR RESEARCH


Characterization of Mg-doped GaN Grown by Metaloragnic Chemical Vapor deposition


Structural studies on MOCVD grown GaN and AlGaN using atomic force microscopy


A new method for a great reduction of dislocation density in a GaN layer on a sapphire substrate

MOCVD法によるサファイア上GaN成長において転位密度低減のための新しい手法を提案した．SiNをバファア層として用いることにより，転位密度が著しく減少することを示した．


Time-resolved spectroscopy of excitonic luminescence from GaN homoepitaxial layers


Dependence of growth conditions on morphology in lateral epitaxial overgrowth of GaN by sublimation method

昇華法によるGaNの選択横方向成長について表面モホロジーと結晶品質の成長条件依存性を調べた．成長温度が上がるにつれて，選択的に成長したストライプの断面形状が三角形から長方形に変化する様子がSEMにより確認できた．またAFMによる観察の結果，ステップ成長により二次元成長することが示された．


Investigation of InGaN/GaN QWs grown on sapphire and bulk GaN substrates

Physica Status Solidi (B) Basic Solid State Physics : PSS


Investigation of optical properties in InGaN/GaN mutiple quantum well and single quantum well


MOCVD-Growth and Transport property investigation of two dimensional electron gas in AlGaN/GaN heterostructures on sapphire substrate


Growth of a GaN layer on a glass substrate by metal organic chemical vapor deposition


V-shaped Defects in InGaN/GaN Multiquantum Wells

MOCVD法により成長されたサファイア基板上InGaN/GaN多重量子井戸構造の欠陥構造を,TEMにより評価した.V欠陥が低温成長GaN試料に対して観察され,貫通転位,混合,刃状転位と密接な関連があることを示した.


Magneto-luminescence spectroscopy of excitonic transitions in homoepitaxial GaN layers


Combined HREELS/LEED Study on the Oxidation of GaN Surfaces

GaN表面の酸化過程を,300-700Kについて高分解能エネルギー損失分光法および低速電子線回折法により調査した.格子振動数の評価から,加熱によりGa酸化物が形成されることを示した.


Configuration of Dislocations in Lateral Overgrowth GaN Films

LEO成長されたGaN膜の転位分布と光学特性を,カソードルミネッセンス法およびTEMを用いて議論した.転位分布と光放出分布は密接な関係があり,転位はバンド端発光強度に影響を及ぼすだけでなく黄色発光に著しく影響を及ぼすことを明らかにした.


Reactive ion etching of GaN and AlxGa1-xN using Cl2/CH4/Ar plasma

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Surface morphology studies on sublimation grown bulk GaN by atomic force microscopy


Formation and Optical Properties of InGaN/GaN Nano-structures Grown on Amorphous Si Substrates by MOCVD

MOCVD法を用いてアモルファスSi基板上に,ナノメータサイズのInGaN/GaN構造を形成し,その光学特性について調査した.


Formation and Optical Properties of Selectively Grown InGaN/GaN Nano-Structures


Large Schottky barriers for Ni/p-GaN contacts


Lateral overgrowth mechanisms and microstructural characteristics of bulk-like GaN layers grown by sublimation method structures Substrates


MOCVD selective growth and characterization of InGaN quantum dots


Excitonic emission under high excitation of hexagonal GaN single crystal grown by sublimation method

Japanese Journal of Applied Physics, Part 2 (Letters)


Fabrication of Nanoscale Structures of InGaN by MOCVD Lateral Overgrowth

ナノメータサイズのInGaN量子線および量子ドットを選択成長法を用い形成できることを示し,その光学特性および転位について議論した.


Investigation on the p-type Activation Mechanism in Mg-doped GaN Films Grown by Metalorganic Chemical Vapor Deposition

MgドープされたGaN中でのp型活性化について調査した.p型活性化のための最適加熱温度と転位との関連を議論した.


InGaN GaN quantum well structures grown on bulk GaN and sapphire substrates

The Journal of the Korean Physical Society


Optical investigation of InGaN/GaN multiple quantum wells


Investigation of Two Dimensional Electron Gas in AlGaN/GaN Heterostructures grown by MOCVD


Role of Dislocation in InGaN Phase Separation

MOCVD成長されたサファイア上のInGaNの光学特性に対する転位の役割をカソードルミネッセンス法およびAFMを用いて議論した.転位は非発光センターとして振る舞うこと,InGaN中の相分離は混合転位によるスパイラル成長により生じることを示した.


Comparison and Investigation of Ohmic Characteristics in the Ni/AuZn and Cr/AuZn Metal Schemes

p型GaNに対する低接触抵抗材料に関して,Ni/AuZnおよびCr/AuZnを検討した.本手法を用いた場合の,電気的特性を示し,その物理機構をTEM,SIMSにより解析した.

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Lateral Obergrowth of Thick GaN on Patterned GaN Substrate by Sublimation Technique


HREELS Analysis of the Vibrational and Electronic Properties of GaN Film on Sapphire(0001) Grown by Metalorganic Chemical Vapor Deposition

MOCVD成長されたGaN膜を高分解能電子エネルギー損失分光法,低速電子回折,ラマン分光法を用いて評価した.本手法を用いることにより,LOおよびTOフォノン周波数およびその異方性,表面付近のキャリヤ密度とその減衰定数を決定した.


Growth of InNAs on GaAs(100) Substrates by Moleculer-Beam Epitaxy

非常に小さなバンドギャップであると予想されるInNAs混晶を分子線エピタキシー法を用いGaAs基板上に成長した.窒素組成38%の混晶が得られた.この結晶は,GaAs基板と格子整合する場合に得られる事を示した.


Characterization of Bulk GaN Grown by Sublimation Technique

昇華法によりつくられたバルクGaNをX線回折,2次イオン質量分析,ラマン散乱分光および電気的特性実験により評価した.本報告で使用したバルク結晶は高い結晶完全性をもち高い純度をもつものであることを示した.


昇華法によるバルクGaN結晶製造技術およびMOCVD法によるホモエピタキシャル成長技術について検討した.バルク結晶の前処理により,ホモエピタキシャル成長後の表面モフォロジー,光学特性が大きく変化することを示した.


Compositional Inhomogeneity of InGaN Grown on Sapphire and Bulk GaN Substrates by Metalorganic Chemical Vapor Deposition

MOCVD成長されたバルクGaN上InGaN膜の組成不均一を,カソードルミネッセンス法およびEDX法を用いて調査した.ホモエピタキシャル膜のIn組成不均一は,サファイア基板上のものよりもはるかに少ない事を示し,実験事実を説明できる物理的モデルを提案した.


p型GaNに対するオーミック接触について調査した.Au-Zn/Ni系金属を用いることにより,非常に小さな接触抵抗になること,および,その物理的機構を,2次イオン質量分析法等などを用いて議論した.


Direct Evidence that Dislocations are Non-radiative Recombination Centers in GaN

平面TEM観察およびカソードルミネッセンス像測定を,n型GaNにおいて同一試料·同一場所に対して行った.カソードルミネッセンス像中の暗点は,TEM像中における転位と1対1で対応することを示した.n型GaN中の正孔の拡散距離を約50nmであると評価した.GaN発光効率は,少数キャリヤの拡散長が転位の間隔よりも短いほど高くなることを実験的に明らかにした.

Japanese Journal of Applied Physics, Part 2 (Letters)


Study of Threading Dislocations in Wurtzite GaN Films Grown on Sapphire by Metalorganic Chemical Vapor Deposition

サファイア基板上に成長したGaN膜中の貫通転位を透過型電子顕微鏡を用いた平面像観察により調査した.刃状転位は低角粒界を形成することを示した.


Surface Pretreatment of Bulk GaN for Homoepitaxial Growth by Metalorganic Chemical Vapor Deposition

昇華法により成長されたバルクGaN上へ,有機金属気相成長法によりホモエピタキシャル成長を行い,バルク表面の前処理効果について検討した.平滑な表面をもち,強いカソードルミネッセンス光を発する試料が,バルク結晶に対して適切な前処理を施すことにより得られた.このカソードルミネッセンス光は,サファイア基板上へ成長させたGaN膜から得られるものよりも強い.また,ホモエピタキシャル膜の転位密度は,適切な前処理により,著しく減少する事を示した.

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Growth of GaN by Sublimation Technique and Homoepitaxial Growth by MOCVD

昇華法によるバルクGaNおよび有機金属気相成長法によるホモエピタキシャル成長について報告している.昇華法における原料粉は,多種類のガリウム,窒素および水素化物から構成される化合物であることを示した.また,有機金属気相成長法におえる核発生制御手法について検討した.六角形柱状結晶が選択的に形成され,本手法がデバイスプロセスに応用できることを示した.

Material Research Society Symposium Proc.


Structural analysis of GaN and GaN/InGaN/GaN DH Structures on Sapphire (0001) Substrate grown by MOCVD

GaN,InGaN/GaNシングルヘテロ構造およびダブルヘテロ構造の格子構造をX線回折を用いた逆格子マッピング法を用いて調査した.特に,ダブルヘテロ構造において,InGaN とキャップGaN層におけるモザイク構造はInGaNの膜厚を20∼110nmに増やすことによって顕著となった.また,モザイク構造に関係した転位が観察された.

Materials Research Society Symposia Proceedings


X-Ray Diffraction Analysis of GaN and GaN/InGaN/GaN Double-Hetero Structures Grown on Sapphire Substrate by Metalorganic Chemical Vapor Deposition

MOCVD法により成長されたサファイア上GaNおよびGaN/InGaN/GaNダブルヘテロ構造の構造解析をX線回折および透過型電子顕微鏡観察により行った.GaN試料については,0.35ミクロン厚の非配向グレイン構造から,1.4ミクロン厚でモザイク構造をもった均一な膜へ遷移することが明瞭に観察された.また,ダブルヘテロ構造においては,膜厚変化に伴うモザイク構造変化および転位挙動について検討した.


Tight-Binding Calculation of Electronic Structures of InNAs Ordered Alloys


XPS Measurement of Valence Band Discontinuity at GaP/GaN Heterostructures

X線光電子分光法により,GaP/GaNヘテロ界面のバンド不連続量を測定した.バンド不連続量ΔEvは,2.3±0.6eVであり,このヘテロ界面は,TypeⅡであることを示した.


MOCVD Growth of InAsN for Infrared Applications

3元混晶InAsNを有機金属気相成長法により,はじめて成長した.減圧成長下で,成長温度をパラメータに実験を行った.X線回折法およびFTIR法により評価した結果,成長温度の上昇およびアンモニア気相比を高くすることにより,窒素の分解を増す事がわかった.また,すべての試料が直接遷移で,窒素組成とともにバンドギャップが減少すること,最小バンドギャップは,InAs(0.939)N(0.061)の試料に対して室温でo.12eVであった.


Transmission Electron Microscopy of Sublimation-Grown GaN Single Crystal and GaN Homoepitaxial Film

昇華法で作製したGaN単結晶上にGaN膜をMOCVD法でホモエピ成長させた．FIB法により加工して電子線が透過する部分を壁状に加工し，結晶内の転位をTEMにより観察した．また，この観察結果に基づき，GaN単結晶内の転位密度を推定した．

Japanese Journal of Applied Physics, Part 2 (Letters)


Growth and Characterization of Thick GaN by Sublimation Method and Homoepitaxial Growth by MOCVD

昇華法を用いて,サファイア基板上への10-30ミクロン厚のGaN厚膜合成に初めて成功した.光励起実験の結果,誘導放出を室温で観測した.

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


X-ray Photoelectron Spectroscopy of Zinc Blend InN and Valence-Band Discontinuity in the Heterojunction InN/GaAs

ジンクブレンド構造InNをプラズマ支援有機金属気相成長法を用いて,GaAs基板上に成長した.X線光電子分光法により,InN/GaAs界面のバンド不連続を調査した.価電子帯バンド不連続は1.3±0.5eVと評価された.

Proceedings of the International Symposium on Blue Laser and Light Emitting Diodes


Photopumped Stimulated Emission from Homoepitaxial GaN Grown on Bulk GaN Prepared by Sublimation Method

昇華法により作成されたバルク基板上のMOCVDホモエピタキシャルGaN膜からの光励起誘導放出を室温で初めて観測した.閾値ポンピングパワーは0.86MW/cm2であり,また,誘導放出光は結晶c軸に対して垂直な電界方向に偏光していることを示した.


Electronic Structures of Wurtzite GaN, InN and their Alloy Ga1-xInxN Calculated by the Tight-Binding Method


Valence-Band-Edge Energy of Group-III, Nitride Alloy Semiconductors


Electronic Structure of Ga1-xInxN by the Tight-Binding Method with Nearest-Neighbor s,p and d and Second-Neighbor s and p Interactions

International Conference on Silicon Carbide and Rerated Materials-1995,Institute of Physics Conference Series


X-ray photoelectron spectroscopy study of GaN and GaP surfaces annealed in PH3 and NH3 and metalorganic chemical vapor deposition growth of GaN / GaP heterostructures

PH3 ，NH3中のGaN，GaPのアニーリング効果について調査し，GaN上のGaP，GaP上のGaNのMOCVD法による成長を行った．それにより次の結果が得られた．約 800℃の低温でのNH3中のアニーリングにより，GaP内にN原子が入り込み，ウルツ鉱型GaN結晶が形成される．しかしGaN結晶の品質は低く，GaP は劣化する．一方，PH3中でのアニーリングでは，GaN中にP原子を導入するためには高温アニーリングが必要である．GaP上に堅いGaNをヘテロ成長させると，基板の品質を劣化させ，逆に，堅いGaNの上に成長させた柔らかいGaPは，基板の品質に大いに影響されること．等がわかった．


Stress Distribution and Dislocation Dynamics in GaAs grown on Si by MOCVD

フォトルミネッセンス法により，Si基板上に成長したGaAs膜中における転位近くの微視的応力分布を調査した．転位近くに存在する格子変形による圧縮応力が観察された．また，鋭い針により外部応力を印加することにより，転位により生じたフォトルミネッセンス像中の暗点が動き，転位の密度や位置をある程度人為的に操作できることを示した．


GaAs/AlGaAs Light Emitters Fabricated on Undercut GaAs on Si

熱応力や転位密度を低減できるUCGAS上にデバイスを成長させることによって，Si基板上で安定した出力のGaAs/AlGaAs LEDを実現できた．UCGAS LEDの出力効率は，ホモエピタキシャル成長で作製したLEDとほとんど同じで，3000時間の安定動作を維持した．残留応力や転位密度と，素子の劣化機構の関係を調査したところ，転位密度より応力が素子の劣化機構に重大な影響を及ぼすことがわかった．また，LEDの出力効率，熱特性も解析した．ホモエピタキシャル成長で作製したレーザーの効率，閾値と同等のUCGASレーザーを作製することができた．


Thermal Stress and Dislocation Density in Undercut GaAs on Si

GaAs/Si界面をポスト成長処理によって部分的に除去されたUCGAS(undercut GaAs on Si)中の，熱応力と転位密度について調べた． 実際の応用に十分な面積において，熱応力が2x108 dyn/cm2未満のものが得られた． SLS(strained-layer superlattice)やGaAs層をUCGAS上で成長させることによって，転位密度を，5x105 cm-2未満にまで小さくすることができた．転位密度を小さくできる理由は，UCGASが成長後の冷却中に応力によって生じる転位に影響されないからである．その結果，UCGASのフォトルミネッセンスのピーク波長やピーク強度は，ホモエピタキシャル成長したGaAsとほぼ同程度にできた．

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Photoluminescence Dark Spot Dynamics in GaAs Grown on Si

Si基板上で成長したGaAsの，室温下におけるフォトルミネッセンス画像において，ある条件下でダークスポットが移動することが明らかになった．Si上のGaAs，UCGAS，GaAs基板上のアンダーカット構造，平面ホモエピタキシャルGaAsなどについて測定し比較したところ，高い応力，高励起の試料では移動するダークスポットの数は多く，移動速度が速かった．この結果は，高温で通常見られるGaAsの転位ダイナミクスと一致している．


Band Gap Energy and Band Lineup of III-V Alloy Semiconductors Incorporating Nitrogen and Boron


Photoluminescence-dark-spot-free AlGaAs grown on Si substrate

Si基板上に成長させたGaAs層をポスト成長処理によって切り離されたUCGAS(undercut GaAs on Si)上でGaAsとAlGaAsを成長させた． 成長した層は，AlGaAs層にある1μm以下のダークスポットをも検出できる高倍率フォトルミネッセンス像によって評価した．その結果UCGASがAlGaAsの欠陥を除去するために非常に効果的であることを示した．


Stable Operation of AlGaAs/GaAs Light-Emitting Diodes Fabricated on Si Substrate

UCGAS構造で非常に劣化の少ないAlGaAs/GaAs LED の作製に初めて成功した． 43K下のフォトルミネッセンスデータから，400℃でアニールするとUCGASの応力が1×108 dyn/cm2以下になることがわかった．800 A/cm2 一定の電流を流したUCGAS LEDの出力パワーは，初めの数時間で初期の値の94%に減少し，その後は1000時間以上一定の出力を維持した．一方，応力が1×109 dyn/cm2以上存在する従来のメサ型LEDの出力パワーは，急速に減少した．

Japanese Journal of Applied Physics, Part 2 (Letters)


InGaAsP/InP Wavelength Division Solar Cells


記事分類: 物理学--分子・物性--結晶

記事分類: 物理学--分子・物性--結晶


Simplified Dual Channel Optical Transmission Using Integrated Light Emitters And Photo- detectors


Theoretical Analysis of Simplified Four Wavelength Division Solar Cell System


Theoretical Analysis of New Wavelength-Division Solar Cells


New Wavelength- Demultiplexing InGaAsP/ InP Photodiodes


Optimum Designing of InGaAsP/InP Wavelength Demultiplexing Photodiodes


Measurement of Diffusion Coefficient and Surface Recombination Velocity for p-InGaAsP Grown on InP


波長多重光通信用InGaAsP/InP光検出器

波長多重光通信用InGaAsP/InP光検出器

電子通信学会論文誌 (C)

電子通信学会論文誌 (C)


ヘテロ接合光ダイオードの量子効率と高速応答特性に関する一考察

電子通信学会論文誌 (C)

電子通信学会論文誌 (C)


InGaAsP/InP Photodiodes Antireflectively Coated with InP Native Oxide


InGaAsP/InP Double- Heterostructure Photodiodes


New method for measurement of electric-field distribution on semiconductors

電界印加下での試料の電界の空間分布測定をコンピューターを用いて測定した．容量性の電界プローブ(AlとSiOにより作製)を用いて，実際に，音響電気効果により電流振動しているCdSの電界分布の測定に成功した．この方法の特徴は，正確な高電界ドメイン電界とそれ以外の領域の電界を自動的に非破壊的に測定できることである．

IEEE Transactions on Instrumentation and Measurement


半導体レーザの周波数スペクトラムの微細構造

半導体レーザの周波数スペクトラムの微細構造


InP上へのInGaAsP層の結晶成長とその光通信用光検出器への応用

InP上へのInGaAsP層の結晶成長とその光通信用光検出器への応用


Growth and Characteristics of GaN Film on Thin AlN/(0001) Sapphire Template Layer via Direct Reaction of Gallium and Ammonia

With the advantages of low cost, simplicity, and scalability, a direct reaction using gallium (Ga) and ammonia (NH3) has been employed to deposit GaN film on a (0001) sapphire substrate. We find that only GaN crystallites with diameters in the range of 0.4-5 μm are sparsely deposited on a bare (0001) sapphire substrate. To increase the density of the GaN nucleation site and thus form continuous GaN film, a 50-nm-thick AlN layer [grown on the (0001) sapphire substrate by metalorganic chemical vapor deposition (MOCVD) at 1150 °C in a pulsed manner] is used as a template layer. Plan-view scanning electron microscopy (SEM) and cross-sectional SEM experimental results show that the GaN film has a specular smooth surface and that the film thickness is about 10 μm after 1 h deposition. X-ray diffraction (XRD) and cathodoluminescence (CL) experimental results indicate that the formed GaN film is of single crystals with a hexagonal structure. The full widths at half-maximum (FWHM) of the (002) and (102) X-ray rocking curves are 420 and 556 arcsec, respectively. Our experimental results demonstrate that the growth of high-quality and thick GaN film via a direct reaction is possible.


Radiative Carrier Recombination Dependent on Temperature and Well WIdth of InGaN/GaN Single Quantum Well

InGaN/GaN 系の量子井戸について，その成長温度，井戸幅との関係を調べた．井戸が深くなるとInGaNは相分離することが確かめられた．


Determination of free carrier bipolar diffusion coefficient and surface recombination velocity of undoped GaN epilayers

キャリヤがp及びn型の場合，それぞれの場合の拡散長をはかった．さらに，GaNの表面拡散長もはかった．


AlGaN/GaN High Electron Mobility Transistor with Thin Buffer Layers

薄いGaNを用いて半絶縁化し，AlGaN/GaNの2次元HEMTを作った．

薄いGaNを用いて半絶縁化し，AlGaN/GaNの2次元HEMTを作った．

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


A Novel Method of Building a Compositional Non-Uniformity in an InGaN Layer Grown on Sapphire Substrate by Metalorganic Chemical Vapor Deposition

始めての100um単位で発光色を変えられる技術を発見した．

始めての100um単位で発光色を変えられる技術を発見した．

Japanese Journal of Applied Physics, Part 2 (Letters)


1 mW AlInGaN-based ultraviolet light-emitting diode with an emission wavelength of 348 nm grown on sapphire substrate


V-Shaped Defects in AlGaN/GaN Superlattice Grown on Thin Undoped-GaN Layers on Sapphire Substrate

Origin and morphology evolution of a self-terminating V-shaped defect in AlGaN/GaN superlattices (SLs) deposited on thin undoped-GaN (u-GaN) layers on sapphire have been investigated using transmission electron microscopy. The V-shaped defects, which generally originated from pits on the top plane of the u-GaN layers with a critical thickness below 500 nm, and deposited with inclined SL structure during the growth of SLs, could terminate in the SL region after propagating to a distance of about 800-1000 nm. The structural variations of the defects could be attributed to the different growth rates between the surrounding matrix and the domains within the defects, at various growth stages.


Influence of Inversion Domains on Formation of V-Shaped Pits in GaN Films


Investigation of phonon emission processes in an AlGaN/GaN heterostructure at low temperatures


Investigation of the emission mechanism in InGaN/GaN-based light-emitting diodes


Current transport mechanism of p-GaN Schottky contactssubstrate by MOCVDstructuresscattering time


Effect of Oxygen on the Activation of Mg Acceptor in GaN Epilayers Grown by Metalorganic Chemical Vapor Deposition

Mgドープp形GaNの活性化アニール中に雰囲気の窒素に酸素を混ぜることで，p形GaNのホール密度などの電気的特性が向上することを見出した．SIMS等による解析の結果，酸素がp形GaN中の水素と反応し，Mgアクセプタを活性化していることがわかった．


time MOCVDstructuresscattering by substrate sapphire on grown layer GaN undoped of quality the on temperature growth and layer buffer of influence The


Effect of silicon-doping on the optical and transport properties of InGaN/GaN multiple quantum well structuresscattering time


Magneto-transport studies of AlGaN/GaN heterostructures grown on sapphire substrates: Effective mass and scattering time


The Influence of Buffer Layer and Growth Temperature on the Quality of Undoped GaN Layer Grown Sapphire Substrate by Metal Organic Chemical Vepor Deposition


Laser-Induced Damage Threshold and Surface Processing of GaN at 400 nm Wavelength


Electron mobility exceeding 104cm2/V.s in an AlGaN-GaN heterostructure grown on a sapphire substrate


Selective etching of GaN over AlxGa1-xN using Reactive Ion Plasma of Cl2/CH4/Ar gas Mixture

Japanese Journal of Applied Physics, Part 1 (Regular Papers & Short Notes)


Effect of Reactive Ion Etching on Yellow Luminescence of GaN


The influence of the p-n junction induced electric field on the optical properties of InGaN/GaN/AlGaN light emitting diodes


Nucleation Control in the Growth of Bulk GaN by Sublimation Method

Japanese Journal of Applied Physics, Part 2 (Letters)