掺杂和热处理对纳ZnO薄膜气敏特性影响

用真空蒸发法在玻璃和单晶硅片上制备纯Zn和掺杂Zn薄膜，然后在高于450 ℃条件下进行氧化、热处理（玻璃衬底）获得良好的纳米ZnO薄膜和掺杂ZnO薄膜。对单晶硅衬底上制备的纯Zn薄膜在高于800 ℃温度条件下进行液态源掺杂，获得掺B和P纳米ZnO薄膜。实验表明，掺杂和热处理使纳米ZnO薄膜的结构、导电性能得到改善，有效地降低了纳米ZnO薄膜的电阻，同时薄膜的气敏特性也得到较大的改善。

离子能量和沉积温度对离子束沉积碳膜表面形貌的影响

利用质量分离的低能离子束沉积技术，得到了非晶碳膜。所用离子能量为50-200eV，衬底温度从室温到800℃。在沉积的能量范围内，衬底为室温时薄膜为类金刚石，表面非常光滑；而600℃下薄膜主要是石墨成分，表面粗糙。沉积能量大于140eV，800℃时薄膜表面分立着高度取向的、垂直衬底表面、相互平行的开口碳管。用高分辨电子显微镜看到了石墨平面的垂直择优取向，离子的浅注入和应用是这种优先取向的主要机理。

自组装InAs/GaAs量子点材料和量子点激光器

利用分子束外延技术和Stranski-Krastanow生长模式，系统研究In(Ga)As/GaAs,InAlAs/AlGaAs/GaAs,In(Ga)As/InAlAs/InP材料体系应变自组装量子点的形成和演化。通过调节实验条件，可以对量子点的空间排列及有序性进行控制，并实现了InP衬底上量子点向量子线的渡越。研制出激射波长λ=960nm，条宽100μm，腔长800μm的InAs/GaAs量子点激光器，室温连续输出功率大于1W，室温阈值电流密度218A/cm~2,0.53W室温连续工作寿命超过3000h。

用硅离子注入SiO_2层方法制备的纳米硅的光学性质

报道了用硅离子注入热氧化生长的SiO_2层后热退火的方法制备纳米硅样品,并在室温下测量了样品的光致发光谱及其退火温度的关系。实验结果表明,在800℃以下退火的样品的发光是由于离子注入而引入SiO_2层的缺陷发光,在900℃以上退火,才观察到纳米硅的发光,在1100℃下退火,纳米硅发光达到最强,纳米硅的发光峰随退火温度升高而红移呈量子尺寸效应。在直角散射配置下,首次观察到纳米硅的特征拉曼散射峰,进一步证实了光致发光谱的结果。

热退火对低温分子束外延GaAs材料深中心的影响

利用光致瞬态电流谱(Optical Transient Current Spectrum OTCS)研究了热退火对低温分子束外延GaAs材料深中心的影响。实验结果表明原生和退火的LT-GaAs中都存在三个主要的深中心LT_1、LT_2、LT_3，退火后各峰的相对强度变化很大，特别L_(LT1)/I_(LT3)=C由退火前的C>>1到退火后C<<1，退火温度越高，C值越小，这主要归因于热退火过程中砷的集聚与沉淀致使与砷反位缺陷As Ga及砷间隙A_(si)相关的Li_1能级浓度的下降，反之，与镓空位V_(Ga)相关的LT_3能级浓度上升。另外经800℃，10min热退火后，在LT_2峰处出现了负瞬态，可能是由于高温退火条件下形成的大尺寸，非共格砷沉淀与GaAs基体间的结构缺陷造成的。

分子束外延生长高应变单量子阱激光器（英文）

采用分子束外延方法研究了高应变InGaAs/GaAs量子阱的生长技术。将InGaAs/GaAs量子阱的室温光致发光波长拓展至1160nm，其光致发光峰半峰宽只有22meV。研制出1120nm室温连续工作的InGaAs/GaAs单量子阱激光器。对于100μm条宽和800μm腔长的激光器，最大线性输出功率达到200mW，斜率效率达到0.84mW/mA，最低阈值电流密度为450A/cm~2，特征温度达到90K。

MOCVD生长InGaAs/InGaAsP多量子阱光泵微碟激光器

用MOCVD方法生长了InGaAs/InGaAsP多量子阱微碟激光器外延片，用光刻、干法刻蚀和湿法刻蚀等现代化的微加工技术制备出直径9.5μm的InGaAs/InGaAsP微碟激光器，并详细介绍了整个制备工艺过程。在液氮温度下用氩离子激光器泵浦方式实现了低阈值激射，测出单个微碟激光器的阈值光功率为150μW，激射波长约为1.6μm，品质因数Q=800，激射光谱线宽为2nm，同时指出微碟激光器射线宽比F-P普通激光器宽很多是由于其品质因数很高造成的。

大功率In(Ga)As/GaAs量子点激光器

利用分子束外延技术和S-K生长模式，系统研究了InAs/GaAs材料体系应变自组装量子点的形成和演化。研制出激射波长λ≈960nm,条宽100μnm,腔长800μm的In(Ga)As/GaAs量子点激光器

二氧化硅覆盖退火增强磷化铟基体激光器材料的量子阱混合

对SiO_2覆盖退火增强InGaAs/InGaAsP/InP激光器材料量子阱混合技术进行了实验研究。相对于原始样品，退火时无SiO_2覆盖的样品经800℃，30s快速退火后，其光致发光谱的峰值波长“蓝移”了7nm,退火时有SiO_2覆盖的样品经过同样的快速退火后，其光致发光谱的峰值波长“蓝移”了56nm。即在同一片子上实现了在需要量子阱混合的区域带隙的“蓝移”足够大的同时，不希望量子阱混合的区域能带结构的变化创记录的大小。该文认为增大量子阱的宽度、采用无应力的量子阱结构以及引入足够厚的缓冲层可以改善量子阱材料的晶格质量，有利于提高量子阱混合技术的可靠性与重复性，改善量子阱材料的热稳定性。

掺铒富硅氧化硅薄膜的光致发光

该文研究了富硅氧化硅薄膜掺入铒的发光特性。富硅氧化硅薄膜(氧含量为60%)采用PECVD方法生长，室温下离子注入铒，经过800℃，5min的退火，在10－～300K温度下得到较强的波长1.54μm光致发光。发光强度随温度升高下降，其温度猝灭激活能为14.3meV。发光谱表明富硅氧化硅中Er-O发光中心仍具有T_d对称性。

分子束外延低温生长GaAs的Raman光谱研究

对从GaAs衬底剥离下来的低温下分子束外延生长的GaAs(LTG-GaAs)薄膜进行了喇曼光谱测量，研究了不同温度下生长的LTG-GaAs在退火前后晶体完整性的变化。首次观测到了190℃生长样品中As沉淀物所引起的喇曼峰，并证明800℃快速热退火30秒后产生的As沉淀物是无定形As。

Effect of rapid thermal annealing on the Raman spectrum of Si0.33Ge0.67/Si (100) alloy

The effect of thermal annealing on the Raman spectrum of Si0.33Ge0.67 alloy grown on Si (100) by molecular beam epitaxy is investigated in the temperature range of 550-800 degrees C. For annealing below 700 degrees C, interdiffusion at the interface is negligible and the residual strain plays the dominant role in the Raman shift. The strain-shift coefficients for Si-Ge and Ge-Ge phonon modes are determined to be 915 +/- 215 cm(-1) and 732 +/- 117 cm(-1), respectively. For higher temperature annealing, interdiffusion is significant and strongly affects the Raman shift and the spectral shape.

Growth and fabrication of high performance 980nm strained InGaAs quantum well lasers using novel hybrid material system of InGaAsP and AlGaAs

In this paper, we report on the design, growth and fabrication of 980nm strained InGaAs quantum well lasers employing novel material system of Al-free active region and AlGaAs cladding layers. The use of AlGaAs cladding instead of InGaP provides potential advantages in laser structure design, improvement of surface morphology and laser performance. We demonstrate an optimized broad-waveguide structure for obtaining high power 980nm quantum well lasers with low vertical beam divergence. The laser structure was grown by low-pressure metalorganic chemical vapor deposition, which exhibit a high internal quantum efficiency of similar to 90% and a low internal loss of 1.5-2.5 cm(-1). The broad-area and ridge-waveguide laser devices are both fabricated. For 100 mu m wide stripe lasers with cavity length of 800 mu m, a low threshold current of 170mA, a high slope efficiency of 1.0W/A and high output power of more than 3.5W are achieved. The temperature dependences of the threshold current and the emitting spectra demonstrate a very high characteristic temperature coefficient (T-o) of 200-250K and a wavelength shift coefficient of 0.34nm/degrees C. For 4 mu m-width ridge waveguide structure laser devices, a maximum output power of 340mW with GOD-free thermal roll-over characteristics is obtained.

Studies of 6H-SiC devices

Silicon carbide (SiC) is recently receiving increased attention due to its unique electrical and thermal properties. It has been regarded as the most appropriate semiconductor material for high power, high frequency, high temperature, and radiation hard microelectronic devices. The fabrication processes and characterization of basic device on 6H-SiC were systematically studied. The main works are summarized as follows:The homoepitaxial growth on the commercially available single-crystal 6H-SiC wafers was performed in a modified gas source molecular beam epitaxy system. The mesa structured p(+)n junction diodes on the material were fabricated and characterized. The diodes showed a high breakdown voltage of 800 V at room temperature. They operated with good rectification characteristics from room temperature to 673 K.Using thermal evaporation, Ti/6H-SiC Schottky barrier diodes were fabricated. They showed good rectification characteristics from room temperature to 473 K. Using neon implantation to form the edge termination, the breakdown voltage was improved to be 800 V.n-Type 6H-SiC MOS capacitors were fabricated and characterized. Under the same growing conditions, the quality of polysilicon gate capacitors was better than Al. In addition, SiC MOS capacitors had good tolerance to gamma rays. (C) 2002 Published by Elsevier Science B.V.

High power 980 nm Al-free strained quantum-well lasers for erbium-doped fiber amplifiers

In this paper, we reported on the fabrication of 980 nm InGaAs/InGaAsP strained quantum-well (QW) lasers with broad waveguide. The laser structure was grown by low-pressure metalorganic chemical vapor deposition on a n(+)- GaAs substrate. For 3 mu m stripe ridge waveguide lasers, the threshold current is 30 mA and the maximum output power and the output power operating in fundamental mode are 350 mW and 200 mW, respectively. The output power from the single mode fiber is up to 100 mW, the coupling efficiency is 50%. We also fabricated 100 mu m broad stripe coated lasers with cavity length of 800 mu m, a threshold current density of 170 A/cm(2), a high slope efficiency of 1.03 W/A and a far-field pattern of 40 x 6 degrees are obtained. The maximum output power of 3.5 W is also obtained for 100 mu m wide coated lasers. (C) 2000 Elsevier Science B.V. All rights reserved.