面向MOCVD生长InAs/GaSb超晶格红外探测的InAs衬底表面制备

采用全反射X射线荧光光谱（total reflection X-ray fluorescence,TXRF）和X射线光电子能谱（X-ray photo-electron spectroscopy,XPS）检测方法研究InAs衬底化学机械抛光后经过不同湿法化学溶液联合作用后衬底表面的金属杂质残留浓度和氧化物组分的变化。湿法化学清洗后的InAs表面检测到金属杂质Si,K和Ca,它们的浓度随溶液组合的变化而变化。金属杂质残留浓度较高的InAs衬底表面同时也测得较多粒径为80 nm的颗粒。提出了一种行之有效的InAs衬底湿化学清洗方法,可制备出金属杂质残留少、颗粒少、氧化层薄InAs衬底表面,此表面有利于MOCVD方法生长高质量InAs/GaSb超晶格红外探测器外延。     

Carbon agent chemical vapor transport growth of Ga2O3 crystal

Beta-type gallium oxide (β-Ga₂O₃) is a new attractive material for optoelectronic devices. Different methods had been tried to grow high quality β-Ga₂O₃ crystals. In this work, crystal growth of Ga₂O₃ has been carried out by chemical vapor transport (CVT) method in a closed quartz tube using C as transport agent and sapphire wafer as seed. The CVT mass flux has been analyzed by theoretical calculations based on equilibrium thermodynamics and 1D diffusional mass transport. The crystal growth experimental results are in agreement with the theoretical predictions. Influence factors of Ga₂O₃ crystal growth, such as temperature distribution, amount of C as transport agent used, have also been discussed. Structural (XRD) and optical (Raman spectroscopy, photoluminescence spectrum) properties of the CVT-Ga₂O₃ crystal are presented.     

无位错Te-GaSb(100)单晶抛光衬底的晶格完整性

采用液封直拉(LEC)法批量生长的直径2英寸(1英寸=2.54 cm)n型Te-GaSb(100)单晶的位错腐蚀坑密度(EPD)通常低于300 cm^-2,达到无位错水平。本文利用X射线摇摆曲线以及倒易空间图(RSM)对这种GaSb单晶抛光衬底的晶格完整性和亚表面损伤情况进行了分析表征,结果表明经过工艺条件优化的化学机械抛光处理,GaSb单晶衬底表面达到原子级光滑,不存在亚表面损伤层。利用分子束外延在这种衬底上可稳定生长出高质量的Ⅱ类超晶格外延材料并呈现出优异的红外探测性能。在此基础上,对CaSb衬底材料的物性、生长制备和衬底加工条件之间的内在关系进行了综合分析。     

Thermally induced native defect transform in annealed GaSb

Undoped p-type Ga Sb single crystals were annealed at 550–600?C for 100 h in ambient antimony. The annealed Ga Sb samples were investigated by Hall effect measurement, glow discharge mass spectroscopy(GDMS), infrared(IR)optical transmission and photoluminescence(PL) spectroscopy. Compared with the as-grown Ga Sb single crystal, the annealed Ga Sb samples have lower hole concentrations and weak native acceptor related PL peaks, indicating the reduction of the concentration of gallium antisite related native acceptor defects. Consequently, the below gap infrared transmission of the Ga Sb samples is enhanced after the thermal treatment. The mechanism about the reduction of the native defect concentration and its influence on the material property were discussed.     

N-type GaSb single crystals with high below-band gap transmission

Te-doped GaSb single crystals are studied by measuring Hall effect, infrared(IR) transmission and photoluminescence(PL) spectra. It is found that the n-type GaSb with IR transmittance can be obtained as high as 60% by the critical control of the Te-doping concentration and electrical compensation. The concentration of the native acceptor-associated defects is apparently low in the Te-doped GaSb compared with those in undoped and heavily Te-doped GaSb. The mechanism for the high IR transmittance is analyzed by considering the defect-involved optical absorption process.     

高品质磷化铟多晶的HGF法合成研究

用高压水平温度梯度定向结晶技术合成了磷化铟(InP)多晶。分析了不同温度梯度对多晶配比度的影响,结果表明当温度梯度低于4℃/cm时,多晶呈明显富铟状态,配比度在97%以下;当温度梯度在5℃/cm以上时多晶致密、无铟夹杂,达到近化学配比状态,配比度达到99%以上。对多晶样品进行了霍尔测试和辉光放电质谱(GDMS)测试,合成的高配比度磷化铟多晶载流子浓度在8×10¹⁵ cm^-3以下,迁移率在3 900 cm²·V^-1·s^-1以上,纯度达到99.999 99%以上。多晶中的杂质主要有Si, S,Fe, Cu, Zn, As等,分析了杂质的来源及其对材料性能的影响。