InP中和C带有关深能级的近红外光致发光

本文用红外光致发光方法研究了InP中与C带有关的深能级的性质和起源。峰值位于价带上0.34eV(77K)附近的宽谱带普遍存在于不同方式生长的InP外延层和掺Sn与不掺杂的衬底中,且与P空位引起的复合缺陷有关。 通过红外光致发光强度对温度的依赖关系得到C带的热激活能为0.17eV。这刚好与采用σ函数来描述深能级的Locovsky模型相吻合,光谱线型与温度猝灭的量子力学位形坐标模型拟合,得到与C带有关的深能级hv=0.02eV,S=8。

INVESTIGATION ON C BAND INFRARED LUMINESCENCE IN INDIUM PHOSPHIDE

The luminescence emission of C band in InP has been studied. The InP samples used in this study were grown by LPE or MOCVD methods. The substrate materials are divided into class A, B, C and D according to the intensity of near band edge luminescence peaks. The MOCVD layers were grown under different conditions including different temperature and M-Y rate. The LPE layers were grown under phosphorus overpressurc with saturated In-Sn melt. The infrared spectra were observed at the temperalurc of 77-30CK with a Kr ion laser as the excitation source and a Ge-detectoi cooled to 77K as the detector. The peak of C band in InP observed in this work is located at 1.08eV and the Spectrum band is broad and weak. It was observed that the C band emission peak shifted slightly to high energy side when the samples were doped heavily. We found that the intensity of C band emission peak depended on the growth conditions and that the intensity of C band in LEP InP decreased if proper component parameter for In-Sn melt was chosen. The experiment result that the C band emission may be observed in both MOCVD and LPE InP samples is consistent with the assumption that the C band is due to lattice defects in InP. By changing the phosphorus pressure during the LPE processes the intensity of C band varies, which is one of the evidences that C band is related to phosphorus defects. The activation energy 0.17eV obtained from temperature dependence of spectra equals to the half of the energy between the deep level, measured directly from C band luminescence, and the top of the valence band. This relationship is expected if a short range potential 6-function replaces, the Coulomb potential in theoretical calculation. The temperature-dependent spectrum results are simulated using quantum mechanics configuration coordination model and the parameters S=8 and hv=0.02eV. It means that a larger Franck-Condon shift exists for C band in InP.