针对中微子和宇宙射线探测用的大尺寸K₂CsSb 光电阴极，本文首先利用光学导纳矩阵法，推导了适用于多层膜的K₂CsSb 光电阴极理论模型。通过该模型对K₂CsSb 光电阴极生长提出了增透层蒸镀、底K 蒸镀、K/Sb 同蒸、进Cs 蒸镀4 个阶段的制备方法，在对各个阶段的反射率变化进行的理论仿真后，发现K₂CsSb 厚度远低于KSb 厚度，整个阴极结构应该为K₂CsSb/K₃Sb/增透层/玻璃的4 层结构；仿真计算结果表明，利用该制备方法获得的K₂CsSb 光电阴极厚度约为40 nm。实验中，由于K 与Sb 同时蒸镀时采用了不同的蒸镀比例会导致截然不同的反射率曲线走势，从而影响到K₂CsSb 的量子效率差异。

To investigate the K₂CsSb photocathode used for neutrinosor cosmic ray detection, a theoretical model of K₂CsSb photocathode for multi-layer films was deduced from the optical admittance matrix method in this paper. Using this model, the four-stage preparation method for the growth of K₂CsSb photocathode had been proposed, which consists of the evaporation of the transmission enhanced layer (TEL), the basic K evaporation, K/Sb co-evaporation, and Cs evaporation. From the theoretical simulation of the changes in reflectivity at each stage, we found that the thickness of K₂CsSb is much less than that of K₃Sb, and the entire structure should be a four-layer configuration: K₂CsSb/K₃Sb/TEL/glass, and the total thickness of the K₂CsSb photocathode is approximately 40 nm from simulations. The experimental results show that the difference in the reflectance curves caused by the difference in the evaporation ratios between K and Sb lead to a difference in quantum efficiency.