Laser-induced defects in crystalline silicon solar cells

Laser based processing has been incorporated into many successful solar cell technologies over the past 20 years; for example buried contact solar cells, laser-fired back contacts and laser texturing. However, the impact of crystal damage generated during laser processing on solar cell performance is still uncertain. This paper investigates laser-induced defects that result from a laser ablation process similar to that used to form grooves in the buried contact solar cell. The first part of this paper focuses on the formation of the defects and uses the Yang etching technique to investigate the impact of chemical etching and thermal cycles on their propagation. The second part of the paper takes a close look at the electrical properties of laser-induced defects, experimentally investigates the recombination of minority-carriers at laser-induced defects, and the potential of these defects to shunt pn-junctions.