The growth model of CdTe thin film by close spaced sublimation

Close spaced sublimation (CSS) has attractive features for high-rate deposition of CdS/CdTe thin film solar modules. CSS has been successfully implemented in commercial production of CdTe solar panels with size of 0.6 m × 1.2 m and 1.2 m × 1.6 m. A CSS growth model is a useful tool to guide the CdTe thin film deposition and the design of CSS. In this paper, a growth model was developed for CdTe deposition including diffusion limited, sublimation limited and reaction limited with the presence of oxygen. The model can explain the effect of source and substrate temperature, ambient gas pressure and the separation between source and substrate on the growth rate of CdTe by CSS. The model may prove very useful for optimization of the CSS process with respect to its design variables (pressure, temperature, etc.).