Periodic Micro Hole Texturing with Metal Assisted Chemical Etching for Solar Cell Applications: Dependence of Etch Rate on Orientation

Abstract

Surface texturing is an indispensable process for solar cell fabrication. The interaction of the surface with the incoming sunlight is controlled by texturing in such a way that the absorption is maximized through multiple interactions. Wet and dry etching techniques have been used to create textured surfaces on solar cells. Other than standard alkaline texturing used by the industry, metal assisted etching (MAE) appears to be a promising texturing technique with greater potential application for multi-crystalline solar cell fabrication. It is possible to achieve both random and periodic patterns with MAE which is relatively cheaper than dry plasma etching techniques. In this study, periodic hole patterns with micron sized diameters and periodicity were aimed to be achieved. Etching rate was shown to be strongly dependent on the surface orientation. Uniformly distributed patterns with various diameter and period values were successfully obtained. Fabrication of solar cells on these surface patters were demonstrated. Performance of solar cells was evaluated through parameters like efficiency, open circuit voltage and short circuit current.