CdZnTe晶体中微米级富Te相与PL谱的对应关系

Correlation between Te-rich Particles in CdZnTe Crystals and Corresponding PL Spectra

采用红外透过显微镜(IRTM)观察了不同条件下生长的CdZnTe晶体中微米级富Te颗粒.结合实际生长条件分析了不同富Te颗粒的产生以及形态演化.通过低温光致发光(PL)谱研究了CdZnTe晶体中杂质、缺陷的状态,以及晶体的结晶质量,并测试了相应晶体的电阻率.归纳出不同富Te颗粒的产生与对应晶体10 K温度下PL谱中特征发光峰之间的关系.研究表明:富Te条件下生长的晶体存在圆形、六边形以及三角形富Te颗粒,PL谱中(D0,X)峰强度占主导;按化学计量比生长的晶体存在十字交叉的富Te颗粒,PL谱中DAP峰强度占主导;Cd过量生长的晶体存在星形富Te颗粒,PL谱中(D0,X)半峰宽较宽.

Micron-scale Te-rich particles presented in CdZnTe crystals were directly observed using infrared transmission microscopy（IRTM）.The generation of various Te-rich particles was discussed in conjunction with the growth conditions.In order to evaluate the impurities and defects behaviors,and to examine the crystalline quality,photoluminescence（PL） spectra were obtained at 10 K.The corresponding resistivity was evaluated simultaneously.The correlation between different shaped Te-rich particles in CdZnTe crystals and the corresponding PL spectra at 10 K was concluded compared with the characterized photo-peak in PL spectra.Well-defined sphere,hexagonal and triangular shaped incoherent Te-rich particles were generally presented in CdZnTe crystals grown from the charge with excess Te,which the（D0,X） peak usually dominated in the PL spectra.Cross-shaped Te-rich particles were found in CdZnTe crystals grown under stoichiometric condition where the DAP peak dominated in the PL spectra.Star-shaped Te-rich particles were normally obtained in CdZnTe crystals under Cd-rich conditions where the FWHM of（D0,X） peak was wide.