Study of CdTe/CdS solar cells using CSS CdTe deposited at low temperature

The authors have prepared thin-film CdTe/CdS solar cells using CdTe deposited by close-spaced sublimation (CSS), at a temperature much lower (~450°C) than the one used in the conventional process (620°C). The CdTe films were treated with the usual CdCl₂ dipping process or with a new process using vapor CdCl₂. The vapor process was much more effective in the recrystallization process, and for the first time the authors observed extensive diffusion of S into CSS CdTe films. They found a direct correlation between the photoluminescence lifetime of the minority carriers and the efficiency-related parameters of the cells. The best cell produced in this work used low-temperature CdTe films treated by vapor and had an efficiency of 11.9%, higher than in cells prepared using high-temperature CdTe films, which shows the potential of this new process to fabricate high-efficiency solar cells