Tunnel oxide passivating electron contacts for high-efficiency n-type silicon solar cells with amorphous silicon passivating hole contacts

Abstract

This study proposes a hybrid solar cell structure for a highly efficient silicon solar cell obtained by combining two passivating contact structures, namely, a heterojunction and polysilicon passivating contact. Given that the major cause of the loss in efficiency of crystalline silicon solar cells is carrier recombination at the metal-semiconductor junction, a passivating contact having high-quality passivation and a low contact resistance was introduced. In this study, two major passivating contact solar cells were combined. By applying an intrinsic thin amorphous silicon layer at the front and a tunneling oxide at the rear, a hybrid silicon solar cell with an efficiency of 21.8% was fabricated. Moreover, to evaluate the potential efficiency limit and to suggest methods for improving the cell performance of the proposed amorphous silicon emitter tunnel oxide back contact structure, the cell efficiency was simulated, and the result indicated that an efficiency of 26% could be achieved by controlling the thickness and resistivity of the wafer.