U型凹槽电极硅MSM结构光电探测器的研制

为了提高硅MSM结构光电探测器的光电响应度,制备了U型凹槽电极结构的探测器。5 V偏压下,对650 nm波长入射光的绝对光电响应度测试表明,凹槽电极结构的探测器最大光电响应度值为0.486 A/W,比同样尺寸的平版结构光电探测器提高了约6倍。文中也对比了具有抗反射膜和不具有抗反射膜的器件相对响应光谱的差别,并且比较分析了叉指间隙分别为5μm和10μm器件光电响应的不同。

Optical and Electrical Properties of GaN.Mg Grown by MOCVD

Mg-doped GaN layers prepared by metalorganic chemical vapor deposition were annealed at temperatures between 550 and 950℃. Room temperature （RT） Hall and photoluminescence （PL） spectroscopy measurements were performed on the as-grown and annealed samples. After annealing at 850℃, a high hole concentration of 8 × 10~(17) cm~(-3) and a resistivity of 0. 8lΩ·cm are obtained. Two dominant defect-related PL emission bands in GaN.. Mg are investigated; the blue band is centered at 2. 8eV （BL） and the ultraviolet emission band is around 3.27eV （UVL）. The relative intensity of BL to UVL increases after annealing at 550℃, but decreases when theannealing temperature is raised from 650 to 850℃, and finally increases sharply when the annealing temperature is raised to 950C. The hole concentration increases with increased Mg doping, and decreases for higher Mg doping concentrations. These results indicate that the difficulties in achieving high hole concentration of 10~(18)cm~(-3) appear to be related not only to hydrogen passivation, but also to self-compensation.

微小孔径激光器的工艺及器件功率和寿命特性分析

在650 nm波长半导体激光器的基础上制造出了高输出功率的微小孔径激光器.驱动电流为25 mA时,输出功率达到0.4mW,最大功率可达1 mW以上.叙述了微小孔径激光器的特殊的制造工艺,并分析了器件可能的失效机理.

掺铒纳米晶硅和掺铒非晶纳米硅薄膜的发光性质

采用等离子体增强化学气相沉积(PECVD)方法制备含有纳米晶硅的SiO2(NCSO)和含有非晶纳米硅颗粒的氢化非晶氧化硅(a-SiOx:H)薄膜.采用离子注入和高温退火方法将稀土Fr掺入含有纳米晶硅(nc-Si)和非晶纳米硅(a-n-Si)颗粒的基体中.利用IFS/20HR傅里叶变换红外光谱仪和微区拉曼散射光谱仪研究含有纳米晶硅和非晶纳米硅颗粒的薄膜掺稀土前后的发光特性.结果表明来自nc-Si在800 nm的发光强度比来自a-SiOx:H基体中非晶纳米硅的发光强度高近一个数量级,而来自a-SiOx:H在1.54 μm的发光强度比NCSO高4倍.还研究了掺铒a-SiOx:H薄膜中Si颗粒和Er3+的发光强度随退火温度的变化,结合掺铒纳米晶硅和非晶纳米硅薄膜发光强度随Er掺杂浓度变化和Raman散射等的测量结果,进一步明确指出a-Si颗粒在Er3+的激发中可以起到和nc-Si同样的作用,即作为光吸收介质和敏化剂的作用

Twinning in Low-Temperature MOCVD Grown GaN on (001) GaAs Substrate

GaN buffer layers (thickness ～60nm) grown on GaAs(001) by low-temperature MOCVD are investigated by X-ray diffraction pole figure measurements using synchrotron radiation in order to understand the heteroepitaxial growth features of GaN on GaAs(001) substrates. In addition to the epitaxially aligned crystallites,their corresponding twins of the first and the second order are found in the X-ray diffraction pole figures. Moreover, { 111 } q scans with χ at 55° reveal the abnormal distribution of Bragg diffractions. The extra intensity maxima in the pole fig ures shows that the process of twinning plays a dominating role during the growth process. It is suggested that the polarity of { 111 } facets emerged on (001) surface will affect the growth-twin nucleation at the initial stages of GaN growth on GaAs(001) substrates. It is proposed that twinning is prone to occurring on { 111 } B, N-terminated facets.

Pt/n-GaN肖特基接触的退火行为

在金属有机物气相外延（MOVPE）方法生长的非故意掺杂的n-GaN上用Pt制成了肖特基接触，并在250-650℃范围内对该接触进行退火。通过实验发现，Pt与非故意掺杂n-GaN外延薄膜可以形成较好的肖特基接触，而适当的退火温度可以有效地改善Pt/n-GaN肖特基接触的性质。在该实验条件下，400℃温度下退火后的Pt/n-GaN肖特基接触，势垒高度最大，理想因子最小。在600℃以上温度退火后，该接触特性受到破坏，SEM显示在该温度下，Pt已经在GaN表面凝聚成球，表面形成孔洞。

单晶硅中氢与辐照缺陷的相互作用

对NTD氢区熔单晶硅进行了不同温度下等时退火，采用Hall电学方法测量了电阻率、迁移率随退火温度的变化规律。利用红外吸收技术测量了单晶硅氢区熔退火前后及NTD氢区熔单晶硅不同退火温度下与氢、辐照缺陷有关的红外振动吸收峰变化，对辐照缺陷的退火行为进行了探讨。实验证实NTD氢区熔单晶硅在150 ～ 650 ℃范围内等时退火具有显著特点

Ge_xSi_(1-x)材料生长的改善

利用超高真空化学气相淀积(UHV/CVD)系统在650℃生长出表面光亮的GeSi单晶。在1200L/min分子泵与前级机械泵间串接450L/min分子泵，改善了生长环境。串接分子泵后生长的样品的X射线双晶衍射分析表明，外延层衍射峰半宽仅为198arcsec，且出现了Pendellosung干涉条纹，说明外延层结晶质量很好。

快速热退火对带有 InGaAs盖层的 InAs/GaAs量子点发光特性的影响（英文）

系统地研究了快速热退火对带有3nm In_xGa_(1-x)As(x=0,0.1,0.2)盖层的3nm高的InAs/GaAs量子点发光特性的影响。随着退火温度从650℃上升到850℃，量子点发光峰的蓝移趋势是相似的。但是，量子点发光峰的半高宽随退火温度的变化趋势明显依赖于InGaAs盖层的组分。实验结果表明In-Ga在界面的横向扩散在量子点退火过程中起了重要的作用。另外，在较高的退火温度下观测到InGaAs的发光峰。

氢离子注入硅片退火行为的高压电镜原位观察

采用高压电子显微镜(HVEM)的原位观察技术，在1MV加速电压和室温至650℃加热条件下，观察了氢离子注入硅片中缺陷层的变化。在500℃以下，氢离子注入缺陷层基本没有变化，在650℃保温时，缺陷的密度逐渐降低，样品中薄区域部分的缺陷在保温20min后消失，而厚区域部分在保温40min后仍存有部分缺陷，说明缺陷的变化与样品厚度有关。用氢的扩散理论讨论了这一现象，提出氢可能是以H_2分子的形式扩散的。

Ti/莫来石陶瓷界面反应的俄歇电子能谱研究

结果表明，在淀积过程中，最初淀积的Ti与衬底表面的氧形成Ti-O键，界面区很窄；450℃退火1h后，有少量元素态Al、Si原子析出，界面区有所展宽，但变化不大；650℃退火1h后，界面发生强烈反应，有TiO和Ti-Al、Ti-Si化合物生成。850℃退火1h后，除上述反应产物外又生成了Ti_2O。

Ti薄膜与AlN陶瓷的界面反应

用X射线衍射分析、二次离子质谱、卢瑟福背散射谱、俄歇电子能谱等表面分析技术，研究了Ti膜与AlN陶瓷衬底的界面固相反应。在高真空中用电子束蒸发的方法在抛光的200℃AlN陶瓷衬底上淀积200nm的Ti膜，并在真空恒温炉中退火。实验表明，退火中Ti膜与AlN界面发生了扩散与反应。650℃，1h退火已观测到明显的界面反应。界面反应产物主要是钛铝化物及Ti-N化合物。铝化物是Ti-Al二元化合物和Ti-Al-N三元化合物，850℃,4h退火后则主要由Ti_2AlN组成。

Polarization switching current of vertical cavity surface-emitting Lasers in an applied electric field

The polarization of vertical-cavity surface-emitting laser (VCSEL) can be controlled by electro-optic birefringence. We calculated the birefringence resulted from external electric field which was imposed on the top DBR of VCSEL by assuming that the two polarization modes were in the same place of the gain spectra in the absence of electric field beginning. By modifying SFM, the affection of the electric field strength on the polarization switching currents between the two polarization modes had been shown.

A study on GaP/Si heterostructures grown by GS-MBE

GaP/Si is a promoting heterostructure for Si-based optoelectronic devices since lattice constants of GaP and Si are so closed that they can match with each other. GaP was successfully grow on (100) Si subtracts by Gas-Source Molecular Bean Epitaxy (GS-MBE) in the study. The GaP/Si heterostructure was characterized by X-ray double crystal diffraction, Anger electron spectrograph, X-ray photonic spectrograph and photoluminescence (PL) measurements. The results showed that the epitaxial GaP layers are single crystalline, in which a parallel to and a (perpendicular to)are 0.54322 and 0.54625 nm, respectively. The peaks in PL spectra of GaP epitaxial layer grown on Si are 650, 627 and 640 nm, respectively. The study demonstrated that GaP/Si is a kind of lattice matched heterostructures and will be a promoting materials for future integrated photonics.