重掺Te的GaSb中缺陷的正电子寿命研究

Positron Lifetime Study of Defects in Heavily Te-Doped GaSb

用正电子寿命谱技术研究了重掺Te的GaSb原生样品、电子辐照样品和质子辐照样品.室温正电子寿命测量揭示出原生重掺Te的GaSb样品中存在VGa相关缺陷,其寿命大小约为298 ps.电子辐照会使该缺陷发生变化,导致平均寿命值减小,VGa相关缺陷从-3价变为-2价.质子辐照后,产生了寿命值较大的缺陷.在10-300K变温实验中,观测到3种样品都存在浅捕获缺陷,该浅捕获缺陷是GaSb反位缺陷.

Heavily Te-doped as-grown GaSb, electron-irradiated GaSb and proton-irradiated GaSb samples were studied by positron lifetime spectroscopy（PAS）. The room temperature lifetime measurement indicated there were VG-related defects with a characteristic lifetime of 298 ps in the heavily Te-doped as-grown GaSb sample. After electron irradiation, this type of defect changed and the average lifetime decreased. It should be due to VGa^3- changing to VGa^2-. Proton irradiation could introduce defects with a high lifetime, and they should be double-vancany defects they may be double-vancany defects. In the temperature dependence measurements which were carried out over the temperature range of 10-300 K, positron shallow trap was observed in all of the three samples, and it should be attributed to positrons forming hydrogenlike Rydberg states with Gash antisite defects.