溶液pH值对化学浴法制备的Cd_xZn_(1-x)S薄膜光电性能的影响

采用氯化镉、氯化锌、硫脲、柠檬酸钠和氨水的溶液体系通过化学浴沉积法合成Cd_xZn_(1-x)S薄膜,利用X射线衍射分析、扫描电子显微镜、能谱仪和紫外可见近红外分光光度计等表征手段研究了Cd_xZn_(1-x)S薄膜的形貌、相结构和光学性能,测试了薄膜的光电流响应曲线并对薄膜的光电性能进行了分析.结果表明:在pH值为10至13范围内成功制备了均匀的Cd_xZn_(1-x)S薄膜;随着pH值升高,薄膜中Zn原子比例与光学带隙减小;制备的薄膜均表现出明显的光电导现象.pH值为11和12时薄膜的表面最为平整致密,结晶性最好,光学带隙分别为2.92eV和2.72eV,光暗电导比均为1.20,光源关闭后电流下降过程最快,10s后电流分别下降了约68.55%和69.39%.

Influence of Solution pH Value on Photoelectric Property of CdxZn1-xS Film Prepared by Chemical Bath Deposition

CdxZn1-x S thin films were prepared by chemical bath deposition in a solution containing cadmium chloride,zinc chloride,thiourea,sodium citrate and ammonia.The morphological,structural and optical properties of CdxZn1-x S films were investigated by X-ray diffraction,scanning electron microscopy,energy disperse spectroscopy and UV-vis-NIR spectroscopy.The photo-current response curves were also tested to study their electrical property.It was found that CdxZn1 xS thin films were successfully prepared at pH values from 10 to 13.With increasing of pH value,the ratio of zinc atom in the film and optical band gap decreased.All the films showed obvious photoconductive phenomenon.The Cdx Zn1-xS films prepared at pH =11 and 12 showed uniform and dense surface morphology and presented good crystallinity.Their optical band gaps were about 2.92eV and 2.72 eV respectively,with light and dark conductivity ratio of 1.20 both.The photo-currents in the samples fell more quickly when the light was turned off,with current reduction of about 68.55％ and 69.39％ after 10s.