Effect of an Underlayer of Cadmium Telluride on the Reflection-Reducing Properties of Zinc Sulfide on Mercury Cadmium Telluride

摘要

For many years ZnS has been used as a passivating coating for HgCdTe photoconductive infrared reflectors. It has served the dual purpose of passivating the surface and acting as an antireflection coating. A recent suggestion in the research Division, NVEOL, was to use a layer of CdTe as the first layer on the HgCdTe surface. It was hoped that better passivation might result because of the properties of CdTe. A final layer ZnS would then be added to achieve further environmental protection and low reflectance. The purpose of this report is to investigate, by computational means, the effect of the underlying layer of CdTe on the reflectance-reducing properties of ZnS. This will be done with absorption coefficient of HgCdTe as a parameter to simulate the effect of cooling the detector to 77 K.