长波长大应变InGaAs/InGaAsP分布反馈激光器的材料生长与器件制备

采用低压金属有机化合物气相沉积法(LP-MOCVD)生长并制作了1.6—1.7μm大应变InGaAs/InGaAsP分布反馈激光器.采用应变缓冲层技术，得到质量良好的大应变InGaAs/InP体材料.器件采用了4个大应变的量子阱，加入了载流子阻挡层改善器件的温度特性.1.66μm和1.74μm未镀膜的3μm脊型波导器件阈值电流低(小于15mA)，输出功率高(100mA时大于14mW).从10—40℃，1.74μm激光器的特征温度T0=57K，和1.55μm InGaAsP分布反馈激光器的特征温度相当.

单边掺杂InAlAs／InGaAs单量子阱中二维电子气的磁输运特性

研究了双子带占据的In0.52Al0.48As／In0.53Ga0.47As单量子阱中磁电阻的Shubnikov-de Haas（SdH）振荡效应和霍耳效应，获得了不同子带电子的浓度、迁移率、有效质量和能级位置．低磁感应强度（B〈1．5T）下由迁移率谱和多载流子拟合相结合的方法得到的各子带电子浓度与通过SdH振荡得到的结果一致．在d^2ρ／dB^2-1／B的快速傅里叶变换谱中，观察到除了通常强烈依赖温度的对应于各子带的频率f1和f2以及f1的倍频（2f1）外，还观察到对温度不敏感的频率f1-f2．这是由于量子阱中不同子带的电子具有相近的有效质量，两个子带之间发生了强烈的磁致子带间散射．

1.3μm InGaAs/InAs/GaAs Self-Assembled Quantum Dot Laser Diode Grown by Molecular Beam Epitaxy

The growth of multi-layer InGaAs/InAs/GaAs self-assembled quantum dots （QDs） by molecular beam epitaxy （MBE） is investigated,and a QD laser diode lasing at 1.33μm in continuous operation mode at room temperature is reported. The full width at half maximum of the band edge emitting peaks of the photoluminescence （PL） spectra at room temperature is less than 35meV for most of the multi-layer QD samples,revealing good,reproducible MBE growth conditions. Moreover,atomic force microscopy images show that the QD surface density can be controlled in the range from 1×10^10 to 7 ×10^10 cm^-2 . The best PL properties are obtained at a QD surface density of about 4×10^10cm^-2. Edge emitting lasers containing 3 and 5 stacked QD layers as the active layer lasing at room temperature in continuous wave operation mode are reported.

快速热退火对高应变InGaAs／GaAs量子阱的影响

用固态分子束外延技术生长了高应变．In0．45Ga0.55As／GaAs量子阱材料．研究了快速热退火对高应变InGaAs／GaAs量子阱材料光学性质的影响．本文采用假设InGaAs／GaAs量子阱中的In—Ga原子扩散为误差函数扩散并解任意形状量子阱的薛定谔方程的方法，对不同退火温度下InGaAs／GaAs量子阱室温光致发光峰值波长拟合，得到了In原子在高应变InGaAs／GaAs量子阱中的扩散系数以及扩散激活能（O．88ev）．

Compressively Strained InGaAs/InGaAsP Quantum Well Distributed Feedback Laser at 1.74μm

The compressively strained InGaAs/InGaAsP quantum well distributed feedback laser with ridge-wave- guide is fabricated at 1.74μm. It is grown by low-pressure metal organic chemical vapor deposition（MOCVD）. A strain buffer layer is used to avoid indium segregation. The threshold current of the device uncoated with length of 300μm is 11.5mA. The maximum output power is 14mW at 100mA. A side mode suppression ratio of 35.5dB is obtained.

A Broadband Long-Wavelength Superluminescent Diode Based on Graded Composition Bulk InGaAs

A novel unselective regrowth buried heterostructure long-wavelength superluminescent diode （SLD） with a graded composition bulk InGaAs active region is developed by metalorganic vapor phase epitaxy （MOVPE）. At a 150mA injection current, the full width at half maximum of the emission spectrum of the SLD is about 72nm, ranging from 1602 to 1674nm. The emission spectrum is smooth and flat. The ripple of the spectrum is less than 0.3dB at any wavelength from 1550 to 1700nm. An output power of 4.3mW is obtained at a 200mA injection current under continuous-wave operation at room temperature. This device is suitable for the applications of light sources for gas detectors and L-band optical fiber communications.

RF-MBE Grown AlGaN/GaN HEMT Structure with High Al Content

A Si doped AlGaN/GaN HEMT structure with high Al content (x= 44%) in the barrier layer is grown on sapphire substrate by RF-MBE. The structural and electrical properties of the heterostructure are investigated by the triple axis X-ray diffraction and Van der Pauw-Hall measurement, respectively. The observed prominent Bragg peaks of the GaN and AlGaN and the Hall results show that the structure is of high quality with smooth interface.fabricated and characterized. Better DC characteristics, maximum drain current of 1.0A/mm and extrinsic transconductance of 218mS/mm are obtained when compared with HEMTs fabricated using structures with lower Al mole fraction in the AlGaN barrier layer. The results suggest that the high Al content in the AlGaN barrier layer is promising in improving material electrical properties and device performance.

HCl/HF/CrO3溶液对 InGaAs/InGaAsP的选择性湿法刻蚀--应用于楔形结构的制备

利用动态掩膜湿法腐蚀技术,研究了HCl/HF/CrO3溶液对与InP衬底晶格匹配的InxGa1-xAs1-yPy(y=0,0.2,0.4,0.6)材料的腐蚀特性.对于HCl(36wt%)/HF(40wt%)/CrO3(10wt%)的体积比为x∶0.5∶1的溶液,随着x由0增加到1.25,相应的腐蚀液对In0.53Ga0.47As/In0.72Ga0 28As06P0.4的选择性由42.4降到1.4;通过调节腐蚀液的选择性,在In072Ga0.28As06P0.4外延层上制备出了倾角从1.35°到35.9°的各种楔形结构;当x为0.025和1.25时,相应的In0.72Ga0.28As0.6P0.4腐蚀表面的均方根粗糙度分别为1.1nm和1.6nm.还研究了溶液的组分与InxGa1-xAs1-yPy(y=0,0.2,0.4)的腐蚀速率间的关系,并对腐蚀机理进行了分析.

宽带偏振不灵敏InGaAs半导体光放大器

采用压应变InGaAs量子阱和张应变InGaAs准体材料交替混合的有源结构,研制了宽带偏振不灵敏的半导体光放大器.此放大器在100～250mA的工作电流范围内,获得了大于70nm的3dB光带宽;在0～250mA工作电流和3dB光带宽波长范围内,偏振灵敏度小于1dB.对于1.55μm的信号光,在200mA的注入电流下获得了15.6dB的光纤到光纤的增益、小于0.7dB的偏振灵敏度和4.2dBm的饱和输出功率.

AlGaN/GaN HEMT电流崩塌效应研究进展

简要回顾了AlGaN/GaN HEMT器件电流崩塌效应研究的进展,着重阐述了虚栅模型、应力模型等几种解释电流崩塌效应形成机理的模型和器件钝化、生长盖帽层等减小电流崩塌效应的措施.

Graded tensile-strained bulk InGaAs/InP superluminescent diode with very wide emission spectrum

A kind of novel broad-band superluminescent diodes (SLDs) using graded tensile-strained bulk InGaAs is developed. The graded tensile-strained bulk InGaAs is obtained by changing only group-III trimethyl-gallium source flow during low-pressure metal organic vapor-phase epitaxy. At the injection current of 200 mA, the fabricated SLDs with such structure demonstrate full-width at half-maximum spectral width of 106 nm and the output light power of 13.6 mW, respectively.

利用GaAs基上InGaAs应变层制备有序排列的InAs量子点

在GaAs基In x Ga1-xAs( x =0.15)应变层上生长了InAs 量子点(QD)层,通过分析各层之间的应力状况和位错的演变过程,配合生长过程中对反射式高能电子衍射仪(RHEED)实时监测,并观察生长后的表面形貌,发现可以通过控制应变层厚度来控制应变层表面布纹结构的宽度,而且在应变层厚度低于位错增殖的临界厚度时布纹宽度较窄.如果同时控制QD层在刚刚出点,则QD主要沿着较窄的布纹结构排列,从而得到有序排列的QD.

Wide-Band Polarization-Independent Semiconductor Optical Amplifier Gate with Tensile-Strained Quasi-Bulk InGaAs

A semiconductor optical amplifier gate based on tensile-strained quasi-bulk InGaAs is developed. At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band-filling effect.Moreover, the most important is that very low polarization dependence of gain (＜0. 7dB),fiber-to-fiber lossless operation current (70～90mA) and a high extinction ratio (＞50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm)and the whole L band (1570～ 1610nm). The gating time is also improved by decreasing carrier lifetime. The wideband polarization-insensitive SOA-gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.

掺杂InGaAs/InAlAs单量子阱中电子对称态和反对称态磁输运研究

利用变温Hall测量研究了重掺杂InGaAs/InAlAs单量子阱中二维电子气,发现在量子阱中由于存在电子对称态和反对称态导致纵向电阻出现拍频现象.通过分析拍频节点位置,得到电子对称态和反对称态之间的能级间距为4meV.此外,通过迁移率谱方法和多载流子拟合过程研究了不同迁移率电子的浓度和迁移率随温度的变化关系.

1.78 μm Strained InGaAs-InGaAsP-InP Distributed Feedback Quantum Well Lasers

Ridge-waveguide distributed-feedback(DFB) lasers with highly strained InGaAs/InGaAsP active regions,emitting at 1.78 μm were fabricated by low pressure metal-organic vapor phase epitaxy(LP-MOVPE) and tested.The lasers exhibited threshold current of 33 mA for 900 μm long cavities at room temperature.A maximum light output power of 8 mW from one facet and an external differential quantum efficiency of 7% were also obtained.In oddition,the side mode suppression ratio (SMSR) is 27.5 dB.