An Alternative Metal-Assisted Etching Route for Texturing Silicon Wafers for Solar Cell Applications

Abstract

Metal-assisted etching (MAE) can be used to form antireflective and light-trapping structures on crystalline silicon solar cells. This method has been widely used to form nanowires and nanoholes on their surfaces. In this study, the MAE technique with additional hole-injection mechanisms has been investigated to form surface nanostructures with various shapes. The effect of each chemical's percentage, as well as the etching time, has been studied on the surface geometry and optical performance. The average reflection from the surface was reduced to less than 3% over the solar spectrum. The light-trapping properties of the structures were investigated through absorption measurements on thin wafers, and a nearly 90% average absorption was obtained for samples with a 50-mu m thickness. The smoothing of the surface and lifetime of the chemical solutions has been systematically studied. As a result, control over the surface geometry and optical properties have been obtained with this new single-step etching approach. Passivation of the surface with SiO2 is also investigated to realize device implementation in the next step.