Chemically microsurface-sphericizing on diamond wire-sawn multi-crystalline silicon wafers by metal-assisted chemical etching and rounding etching

The combination processes of metal-assisted chemical etching (AgNO3 + HF + H2O2) and rounding etching (HNO3 + HF + H2O) were used for the texturization of diamond wire sawn (DWS) multi-crystalline silicon (mc-Si) wafers. The evolution of texture structure on the DWS mc-Si wafers was investigated in detail. The chemically microsurface-sphericizing (CMS) textures, which were nearly smooth spherical structure with a size of approximately 2–3 μm, were fabricated successfully on the DWS mc-Si wafers with the combination processes. Compared with the conventional metal-assisted chemical etching (MACE) textures, the CMS textures were improved on surface recombination and the filling of electrode, thereby boosting the electrical performance of the solar cells and the cell-to-module (CTM) loss at the module end. These CMS textures resulted in an increase in the output power of the photovoltaic module by 0.047 W per cell. The fabrication of these CMS textures may be easily scaled up in the photovoltaic production line.