Ammonia pretreatment influence on the defect properties of Cu (In, Ga) Se/sub 2/solar cells from admittance spectroscopy
Résumé
In thin film polycrystalline CdS/CIGS heterojunction solar cells, understanding the intrinsic and interface defect properties is crucial to optimize their performances. In this paper, we focus our attention on the CdS/CIGS hetero-interface at different stages of its formation. All investigations were carried out on CIGS co-evaporated samples elaborated in pilot-line conditions onto which the CdS layer was deposited by chemical bath deposition (CBD). This latter chemical process involves the use of a NH, solution that modifies the ClGS surface composition. In order to separate the respective role of the NH/sub 3/ bath and the CdS layer thickness , we have investigated samples elaborated with several NH/sub 3/ pretreatment time of CIGS surface prior to CdS deposition. Admittance spectroscopy was used to follow the evolution of the hetero-interface defects properties.