CdZnTe晶体光致发光谱“负热淬灭”现象研究

Study on Negative Thermal Quenching of PL in CdZnTe Crystal

采用改进的垂直布里奇曼法生长了直径为60mm的CdZnTe晶体,测试了其在10K～150K范围的PL谱。对760nm和825nm处的峰积分强度随温度变化关系进行研究发现,在30～50K范围内,PL谱峰的强度呈现反常温度依赖现象,即随着温度的升高而减小,也就是所谓的"负热淬灭"现象,这在CdZnTe晶体中属首次观察到。进一步分析表明,随着温度的增加,其PL谱强度变化的过程包含了三个无辐射过程和一个负热淬灭过程。与没有发生"负热淬灭"现象的CdZnTe晶体对比,两者XRD图谱呈现明显差异。讨论了发生负热淬灭现象的原因以及可能路径。

Photoluminescence （PL） spectroscopy was carried out on CdZnTe crystal grown by Modified Vertical Bridgman method,with temperature from 10 K to 150 K.Abnormal temperature dependent PL intensity were observed from 30 K to 50 K,which is the so-called ＂negative thermal quenching＂.Three non-radiative processes and one negative thermal quenching process were identified.The difference of XRD spectra between CdZnTe crystals with and without negative thermal quenching behaviors gives a possible explanation on its origin.