CdZnTe薄膜的CdCl_2退火及性能表征

Effects of CdCl_2 thermal annealing on CdZnTe thin films deposited by close-spaced sublimation

采用近空间升华法制备了CdZnTe薄膜,并对其进行CdCl2退火,采用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、紫外光谱仪、I-V测试仪等研究了退火对薄膜表面形貌、成分、结构以及光电性能的影响。结果表明,经过CdCl2退火后薄膜的晶粒尺寸明显增大,晶粒分布更加均匀;XRD分析结果显示,退火后薄膜的最强峰(111)峰的半峰宽变窄,薄膜沿(111)方向的择优取向明显增强;退火后薄膜的光学透过率降低,截止边红移,光学禁带宽度减小;薄膜的电阻率在退火后下降了两个数量级。

The CdZnTe polycrystalline thin films were deposited by close-spaced sublimation （CSS） and then annealed with CdCl2 coating. The influences of the CdCl2 annealing on the morphology, composition, structure and optical properties of the films were studied by SEM, EDS, XRD, UV spectrophotometer, and I-V measurements. The SEM results show that after annealing the grains are more uniform, and the grain sizes are increased significantly. The XRD results show that the FWHM of the （111） peak, which is the strongest diffraction of the CdZnTe films, reduced and the （111） texture is enhanced after annealing. The optical transmittance decreases and the forbidden edge shifts toward longer wavelengthwith, indicating the decrease of the optical band gap.The resistivity of the film decreases by two orders of magnitude after annealing.