Si/Znx Cd1-x Te heterostructures with different Zn contents: Growth, electrical and photoelectrical properties

Abstract

The ZnxCd1-xTe films with x = 0 ÷ 0.97 are grown by vacuum deposition in quasiequilibrium conditions on single crystal Si (111) substrates. The details of the growth process were analyzed. The possibilities of the quasi-closed volume method for producing high quality homogeneous layers of solid solutions were evaluated. It is shown that this method is very effective for the production of films with x < 0.1 and may be implemented at condensation temperatures up to ∼ 300°C. Studies of electrical and photovoltaic properties showed high quality of ZnxCd1-xTe layers and structures in general. This is, in particular, evidenced by increasing photosensitivity in the region of absorption of the film material, and of the structure as a whole, increasing integral sensitivity with zinc doping, a significant reduction in nonideality factor in solid solution films as compared with CdTe films. We have established an increase of mechanical stability of the structure with increasing Zn content, expressed in maintaining the strength during repeated thermal cycling. As a result, the manufactured Si/ZnxCd1-xTe heterostructures can serve as a basis for fabrication of multijunction solar energy converters.