An overview on the role of ZnTe as an efficient interface in CdTe thin film solar cells: a review

Abstract

The present era of cutting edge technology requires environmentally friendly alternative energy resources due to the limited fuel reserves and the emission of pollutants associated with the use of conventional resources such as fossil fuels. Since the invention of CdTe-based solar cells, they have become potential suitable alternatives and competitors to silicon solar cells owing to their cost effectiveness and stability. Thus, the development of CdTe thin film solar cells has gained significant attention due to their potential roles as sustainable energy sources. To develop higher efficiency CdTe-based thin film solar cell devices, typically, a zinc telluride (ZnTe) layer is employed as an essential interface between the CdTe absorber and metal contact. The superiority of the ZnTe back contact improves the shunting pathway to the motion of charge carriers, which eventually enhances the device performance. With the use of a supporting CdSeTe absorber and magnesium-doped zinc oxide (MZO) optical window together with a ZnTe back contact, these devices are commonly utilized not only in single junction devices but also tandem devices. This review presents major improvements in the power conversion efficiency of CdTe thin film solar cells in detail with special reference to the ZnTe back contact layer. It also highlights various thin film deposition techniques together with the impact of doping and post-deposition treatment on ZnTe thin films to enhance the related properties, followed by the importance of the present study.