P型掺杂GaAs液相外延材料的辐射复合研究

Radiative recombination in p-type doped GaAs grown by liquid-phase epitaxy

对Ｓｉ掺杂和Ｚｎ掺杂ｐ型ＧａＡｓ液相外延材料在３００Ｋ～６０Ｋ温区的辐射复合进行了光致发光研究。用发射波长为５１０．６ｎｍ和５７８，２ｎｍ的溴化亚铜激光器作为激发光源，样品的低温由氦循环制冷机提供，样品室温度在１０Ｋ～３００Ｋ中可调。主所选取的狭缝宽度下，谱仪的分辨率大致为２ｎｍ．本文所提供的数据全部经过系统灵敏度校正并进行分峰拟合。本文讨论了Ｓｉ掺杂ｐ型ＧａＡｓ样品ＰＬ谱中一些主要特征。认为Ａ１、Ａ２、Ａ３三个发射带分别对应着导带“尾”态中电子向价带和两个浅受主能级的跃迁。其温度依赖关系和带隙宽度及电子填充状态随温度变化有关。此外，我们还观察了掺Ｚｎ的ｐ型ＧａＡｓ样品的ＰＬ谱。与接Ｓｉ样品比较，具有明显不同的特征。谱线在长波端（～９５０ｎｍ）的上扬趋势表明可能在低能区域存在一个与深能级复合有关的宽发射带。

The redtative recombination in p-type GaAs doped with Si and Zn prepared by liquid-phase epitaxy have been studied by photolunminsecence between 300K and 60K.The photoluminescence(PL) spectra were obtained by CuBr-laser with wavelengths 510.6nm and 578.2nm excitation.The resolution of spectrometer at the slit width used was about 2nm The daal shown were corrected for its r￣nse.The lowtemperature dais were obtained with the speimens mounted on acold finger in a COOler with He-circle system. In the p-type Si-doped GaAs material,three emission bands A1,A2 and A3 can be explained in terms of recombination processes involving the transitions from conduction band('tail')to valence band,shallow(￣40meV)acceptor states and deep(￣100meV)acceptor stated respeCtively.The dependence of peak energy and relative intensity on temperature were discussion.The PL spectra of a Zn-doped sample which characteristics are obviously different from those of Si-doped Samples were also observed,Its ascenting trend in the longer wavelength side(￣(950nm)suggests that there may be a wide emission band involving a deep energy level(￣ recombination in lower energy region.