Enhancement of electrical parameters in solar grade monocrystalline silicon by external gettering through sacrificial silicon nanowire layer

Abstract

In this work, we report a simple and efficient purification technique of solar grade silicon wafers suitable for high efficiency and low-cost silicon solar cells. This gettering method requires the elaboration of silicon nanowire thin layer followed by an annealing treatment and removing impurity loaded silicon nanowires. ICP-AES analysis shows a significant decrease in the metallic impurity concentration resulting considerable enhancement in the silicon purity grade. Electrical characterizations reveal a global decrease of the majority carrier concentration and a substantial improvement of the minority carrier lifetime. Furthermore, the application of this novel gettering process induces an enhancement in the silicon solar cell electrical parameters. These results give evidence of the effectiveness of the proposed purification method to produce efficient solar cells starting from low-quality silicon wafers.