The Effects of Fabrication Prameters and Electroforming Phenomenon on CdTe/Si (p) Heterojunction Photovoltaic Solar Cell

Abstract

The In-doped CdTe/Si (p) heterostruture was fabricated and its electrical and photoelectrical properties were studied and interpreted. During the fabrication processes of CdTe/Si heterojunction, some practical troubles were encountered. However, the important one was the formation of the SiO 2 thin oxide layer on the soft surface of the Si during the formation of the back contact. The silicon wafer was subjected to different chemical treatments in order to remove the thin oxide layer from the silicon wafer surfaces. It was found that the heterojunction with Si (p + ) substrate gave relatively high open circuit voltage comparing with that of Si (p) substrate. Also an electroforming phenomenon had been observed in this structure for the first time which may be considered as a memory effect. It was observed that there are two states of conduction, non-conducting state and conducting state. The normal case is the non-conducting state. As the forward applied voltage increased beyond threshold value, it switches into the conducting state and remains in this state even after the voltage drops to zero.