High quality textured ZnO:Al surfaces obtained by a two-step wet-chemical etching method for applications in thin film silicon solar cells

ZnO:Al films deposited at 250 °C on Corning glass by radio frequency magnetron sputtering were studied for their use as front contact for thin film silicon solar cells. For this purpose, a two-step etching method combining different concentrations of diluted hydrochloric acid (from 0.1% to 3%) with different etching times was developed. Its influence on morphological, electrical and optical properties of the etched films was evaluated. This new etching method led to more uniform textured surfaces, where the electrical properties remained unchangeable after the etching process, and with adapted light scattering properties similar to those exhibited by commercial substrates.