Study of CBD-CdS/CZTGSe solar cells using different Cd sources: behavior of devices as a MIS structure

CdS buffer layer plays an important role in thin film solar cells; as a result, a deep understanding of its physical properties and impact on solar cell performance is highly required. In this work, we report results on growth conditions of CdS thin films deposited by chemical bath method to be used as insulators in MIS structure instead of the traditionally assumed p–n junction. Three different Cd sources—CdCl2, Cd(NO3)2, and CdSO4—are considered for CdS processing. The impact of Cd source on CdS physical properties as well as on the electro-optical device properties of CdS/CZTGSe solar cells is evaluated. Furthermore, interface state properties are calculated as a function of temperature. These states are a result of the CdS interaction with both the TCO and Kesterites, depending on the Cd source used in solution of the chemical bath deposition. Besides, some important requirements to be considered in order to improve device efficiency are discussed in the present work.