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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 effect of pH on the properties of CdS thin films prepared by chemical deposition was studied experimentally. The results show that the phase transition of CdS film occurs from the cubic phase to the hexagonal phase with the increase of the concentration of ammonia in solution in the system of sodium citrate as complexing agent, that is, when the ammonia concentration is 0 31M, the cubic phase CdS Film; and when the ammonia concentration is greater than 0 51M, to obtain a hexagonal CdS film. The increase of ammonia concentration also made the morphology of CdS thin films much better, and the prepared CdS thin films changed from Cd-rich to S-rich, but the films were still n-type. The concentration of ammonia water also has a great influence on the optical properties of CdS films. The band gap of CdS films increases with the increase of ammonia concentration.