近空间升华法制备CdZnTe外延厚膜及其性能研究

Growthand characterization of thick epitaxial CdZnTe film by close space sublimation

采用近空间升华法在GaAs(100)衬底上外延生长CdZnTe单晶厚膜,用化学腐蚀的方法去除掉GaAs(100)衬底后,对CdZnTe外延膜上、下表面的形貌、成分、结构以及电学性能进行了表征分析。SEM和EDS的结果表明,CdZnTe外延膜表面平滑致密且膜中成分分布较均匀;红外透过成像分析的结果表明,CdZnTe厚膜中无明显的Te夹杂相;X射线摇摆曲线、PL谱的结果表明,随着薄膜厚度的增加,CdZnTe外延膜中的晶体缺陷减少,应变弛豫,结晶质量提高,通过增加膜厚可以获得高质量的CdZnTe外延膜;电学测试表明,CZT外延膜的电阻率在1010Ω·cm数量级,且具有较好的光电响应特性,可用于高能射线探测。

The close space sublimation method was used for the epitaxial growth of thick CdZnTe single crystal films for high-energy radiation detectors.High quality CdZnTe epilayers had been successfully grown on a GaAs（100）substrate by CSS method.Crystalline quality of the upper and lower surfaces of the epilayer was as-sessed from X-ray rocking curve measurements and photoluminescence（PL）spectra after GaAs（100）substrate had been removed by Chemical etching.The density of defects in the epilayer decreases with increasing the thickness,which suggests that the high-quality epilayer can be obtained by increasing the thickness.No Te in-clusions in the CdZnTe films grown on GaAs（100）were observed with IR transmission imaging.The film resis-tivity was in the order of 10^10 Ω·cm,which shows a good photoelectric property.