Understanding Contact Formation on n-PERT-RJ Solar Cells

Abstract

In this work we investigated the metallization process of screen-printed n-type passivated emitter rear totally diffused (n-PERT) rear junction (RJ) silicon solar cells. We used the voltage calibrated photoluminescence (PL) method to extract the saturation current density on the laser ablated surface before metallization (J0-abl) and at the metal-silicon interface after metallization (J0-met). Symmetrically diffused and passivated test samples, printed with specific metallization patterns, were fabricated for this purpose. We investigated the influence on J0-met varying boron (p+) and phosphorous (n+) diffusions, cleaning after laser ablation, metal pastes and peak firing temperature. The optimum parameters were then applied to fabricate n-PERT-RJ cells.