pH值对化学沉积制备CdS薄膜性质的影响

THE PROPERTIES OF CdS THIN FILMS WITH VARIOUSpH BY CHEMICAL BATH DEPOSITION

实验研究了pH值对化学沉积制备CdS薄膜性质的影响。表明:在柠檬酸钠作为络合剂的体系中随着溶液中氨水浓度的提高CdS薄膜会发生相变,从立方相变为六方相,即当氨水浓度为0 31M时,得到立方相的CdS薄膜;而当氨水的浓度大于0 51M时,得到六方相的CdS薄膜。氨水浓度的提高也使得CdS薄膜的形貌有了很大的改善,且制备得到的CdS薄膜从富Cd变为富S,但是薄膜仍是n型。氨水浓度对CdS薄膜的光学性质也有很大的影响,随着氨水浓度的提高所得到的CdS薄膜的禁带宽度增大。

The properties of CdS thin films with various pH was investigated.It revealed that the structure of CdS thin film is cubic as the ammonia concentration of 0.31M and the structure of CdS thin film is hexagonal as the ammonia concentration larger than 0.51M in the experiments.The structure transformation was found as the increasing of the ammonia concentration.The morphology of CdS thin films was improved and the CdS thin film was transformed from Cd rich to S rich with the increasing of the ammonia concentration,but the conductivity type of thin films was not change.The ammonia concentration has greatly influenced the optical properties and the band gap of CdS thin films.