Improved front side metallization for laser doped solar cells

Abstract

A simple but effective way to create a selective emitter is by using laser doping (LD) to selectively remove the anti-reflection coating (ARC) layer and simultaneously melt the silicon underneath it while incorporating dopants into the melted region, creating a heavily doped layer. In conjunction with LD, a plating technique is often used to selectively plate self-aligned metal contacts onto the laser doped lines. For light induced plating (LIP), the significant advantage compared to ordinary electroplating processes is that no electrical contacts are required to be connected to the front side metal grid as the illuminated solar cell itself generates the required current serving as both the cathode and anode of the reaction. This is also the reason why this plating technique has the potential to provide a very uniform layer provided a reasonably uniform light source is used to illuminate the cell surface. In this paper, we have improved the front side metallization for laser doped solar cell via a pre-treatment prior to Ni plating. The cells with homogenous Ni film have higher FF, so we have obtained over 19% conversion efficiency.