摘要
本文用4.2K光致发光研究了LEC GaAs的热感生缺陷.热退火时样品分别为无包封,包封或用一个未掺杂的SI-GaAs片覆盖.退火温度为650-850℃,退火在不同气氛下进行(真空,H_2,N_2,H_2+N_2或H_2+As_2). 与缺陷有关的发光带有1.443eV,1.409ev和0.67eV发光带.1.443eV发光带不仅在富Ga的GaAs中出现,而且在富As的热稳定性好的SI-GaAs晶体并经过850℃(在H_2中)热退火的样品中也观测到此发光带.这可能是在退火过程中促进反位缺陷GaAs的形成.1.443eV发光带与GaAs有关.GaAs晶体在H_2中退火后1.409eV峰很强,但在真空中退火末探测到此发光带.文中提出它可能是热退火时氢原子扩散到GaAs晶体中并与某些缺陷结合成络合物的新观点.
Photoluminescence of thermal annealing-induced defects in GaAs was investigated at 4.2K.Annealing treatments on the samples of capless, encapsulated or covered with an undoped LECSI-GaAs wafer were carried out in the temperature interval 650-850℃ in different ambience(vacuum, H_2,N_2,H_2+N_2 or H_2+As_2) Three emission bands related to defects have been observed at 1.443 eV, 1.409 eV and 0.67eV in SI-GaAs. The emission band at 1.443 eV has been found not only in Ga-rich as-grownGaAs, but also in some slightly As-rich SI-GaAs samples,which had been annealed in hyd-rogen atmosphere at 850℃ and have excellent thermal stability.The experimental results sup-port the suggestion that 1.443 eV band is associated with Ga_(As).The intensity of 1.409 eV bandis very strong when the GaAs was annealed in hydrogen atmosphere.However, it is undetec-ted for the samples annealed in vacuum. We propose a new model suggesting that he emis-sion hand at 1.409 eV is probably associated with a complex of some kind of defects and hyd-rogen atoms, which are diffused into the crystals during the heat treatment.
基金
国家自然科学基金
