采用化学浴沉积法将氯化镉、氯化铵、硫脲和氨水的溶液体系合成CdS薄膜,用扫描电子显微镜、X射线衍射仪和紫外可见吸收光谱等研究了CdS薄膜的形貌、相结构和光学性能,通过测试薄膜的光电流响应曲线分析了薄膜的光电性能.结果表明:溶液的pH值在9~11的范围内均可以制备均匀致密的CdS薄膜,其中pH=10时制备的CdS薄膜最为均匀致密且其X射线衍射仪衍射峰强度最强,对应的光学带隙约为2.37eV;光电流响应曲线显示该薄膜的光电导最高为2.94×10-2Ω-1·cm-1,光暗电导比为38.23,具有最佳的光敏性.
The CdS thin films were prepared by chemical bath deposition in a solution containing cadmium chloride,ammonium chloride,thiourea and ammonia. The morphological,structural and optical properties of CdS films were investigated by scanning electron microscope,X-ray diffraction and UV-visNIR spectroscopy.The photo-current response curves were also tested to study the optoelectrical performance of the films.It was found that uniform and compact CdS films could be prepared using pH values from 9to 11.The CdS film prepared at pH=10showed a most dense surface morphology and presented strongest peak intensities of the X-ray diffraction patterns and a band gap of about 2.37 eV.According to photo-current response results,the CdS film with best quality has a highest photoconductivity of 2.94×10-2Ω-1·cm-1 and a largest light and dark conductivity ratio of 38.23.