Surface modification of diamond wire sawn multi-crystalline silicon wafers by grinding pre-treatment for wet acid texturization

Abstract

Grinding as a pre-treatment method for HF-HNO3-H2O solution etching of diamond wire sawn (DWS) multi-crystalline (multi-Si) silicon wafers was proposed and researched. Significant improvement in morphological uniformity and decrease in light reflectivity of the wet acid etched surface textures were achieved with the pre-treatment. The photoelectric-conversion efficiency gain of solar cells fabricated with the pretreated DWS multi-Si wafers was 0.32%, compared to solar cells fabricated with the same batch of untreated wafers in an identical production line. The grinding pre-treatment was observed to restructure the superficial layer of DWS multi-Si wafers. The surface modification layer was believed to be more easily reacted with the wet acid etching solution, proving responsible for the improvement of photoelectric-conversion efficiency of solar cells. This method could provide a new research idea for the wet acid texturization of DWS multi-Si wafers.