The impact of thermal treatment on gettering efficiency in silicon solar cell

Abstract

This paper describes a study to understand the impact of heat treatment on the crystal Silicon (c-Si) with developed surface by Aluminum /Porous silicon (Al/PS) and evaluating their influence on the solar cell performance. In fact, the heat treatment of silicon surfaces with PS/Al is an effective means of structural and electrical adjustment and performance improvement of c-Si solar cells. The new process could be accomplished by a two-step annealing in order to benefit from both the high and low temperature processes. The advantages of such a new getter in comparison with traditional getter were demonstrated in various devices. We can estimate that the resistivity using the standard Van Der Pauw, and LBIC measurements have been performed to determine the diffusion length. The resistivity of crystalline silicon decreased when the porous layer was removed at about a depth around 70μm. As a result, we found amelioration in the I–V characteristics and an enhancement of minority carrier lifetime. It has been shown that this simple method leads to improve the charge carrier collection and the electrical properties of c-Si based solar cells.