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.