Investigation of laser ablation on boron emitters for ntype rear-junction PERT type silicon wafer solar cells.

n-type silicon wafer solar cells are receiving increasing attention for industrial application in recent years, such as the n-type rear-junction Passivated Emitter Rear Totally-diffused (PERT) solar cells. One of the main challenges in fabricating the n-PERT solar cells is the opening of the rear dielectric for localized contacts. In this work laser ablation is applied to locally ablate the rear dielectric. We investigate the laser damage to the emitter at the laser-ablated regions using the emitter saturation current density, J_oe,laser, extracted by two approaches. J_oe,laser is observed to be injection dependent due to high J_o2 recombination caused by laser damage to the space charge region. By using the optimized laser ablation parameters, n-PERT solar cells with an efficiency of up to 21.0% are realized. [ABSTRACT FROM AUTHOR]