正电子湮没谱和光致发光谱研究掺锌GaSb质子辐照缺陷

Defects in proton-irradiated Zn-doped GaSb studied by positron annihilation and photoluminescence

用正电子湮没谱和光致发光谱研究了质子辐照后掺锌GaSb中的缺陷.通过分析正电子的缺陷寿命τ2及强度I2的变化发现,在高能质子的辐照下产生了双空位缺陷VGaVSb,可能同时产生了小的空位团.正电子平均寿命τav和S参数随着质子辐照剂量的变化也证明了这一结论.通过分析不同质子辐照剂量下掺锌GaSb的光致发光谱,发现GaSb中的Zn没有与辐照缺陷相互关联.质子辐照在样品中产生了非辐射复合中心.这种非辐射复合中心很可能是双空位和小空位团.利用光致发光谱推算了受主杂质Zn在GaSb中的能级位置.在经过质子辐照后的样品中发现了氢的存在,氢充当了浅受主杂质.通过退火实验观察到了样品中空位型缺陷的迁移合并和分解,发现氢原子加强了缺陷的移动能力.

Positron annihilation spectroscopy（PAS）and photoluminescence（PL） have been adopted to study defects in proton-irradiatied Zn-doped GaSb.A monovacancy VGa having a lifetime of 293 ps was observed in the non-irradiated sampls and a divacancy VGaVSb with a tifetime of 333 ps was identified in the proton-irradiated samples when the fluence reached 3×1015 cm-2.The PL results reveal that the acceptor Zn is not related with proton irradiation-induced defects,which act as non-radiation recombination centers in the samples.The acceptor level of Zn in GaSb has been calculated from the PL spectra.After proton irradiation,interstitial monatomic hydrogen in a negative charge state（Hi-） in GaSb has been found,which acts as a shallow-acceptor.Annealing experiments indicated that the as-grown and proton-irradiated samples have different annealing behaviors,the reason for which was attributed to the existence of monatomic hydrogen interstitials in the proton-irradiated samples.