Impact of CdSeTe and CdSe film deposition parameter on the properties of CdSeTe/CdTe absorber structure for solar cell applications

Abstract

In this study, the effect of depositing CdSeTe and CdTe layers at different substrate temperatures by evaporation in vacuum on the properties of the CdSeTe/CdTe stacks was investigated. First, CdSeTe layers in stack structure were grown at substrate temperatures of 150, 200 and 250°C and then CdTe layers on the CdSeTe produced with the optimum temperature were coated at substrate temperatures of 150, 200 and 250°C. The employing of substrate temperatures up to 150°C on both CdSeTe and CdTe films in CdSeTe/CdTe stacks demonstrated the presence of Te and/or oxide phases as well as the alloying, while more stable phase structures at higher temperatures. In the CdSeTe/CdTe stack, the increase in substrate temperature of CdSeTe promoted the alloying, while it weakened the alloy in which was applied in CdTe. It was concluded that under the applied experimental conditions, substrate temperatures of 250°C and 200°C with the graded alloying structure, suitable absorption sites, more homogeneous surface morphology for potential solar cell applications would be more suitable for CdSeTe and CdTe, respectively. As a result, the application of substrate temperature to CdSeTe or CdTe in the stacks can be used as a tool to control the properties of the stack structure.