Reactive ion etching surface texturing of c-Si using silica nanosphere lithography technique for solar cell application

Abstract

A reactive ion etching (RIE) process has been applied to etch diverse shape of nanoscale surface texturing on crystalline silicon (c-Si) for solar cell application. In this work, silica nanospheres (NS) were used as a mask material to utilize selective etching between silicon surface and silica NS for texturing. For effective silica NS deposition, we also developed our own solvent-control spin-coating method showing great monolayer coverage under common laboratory environment which is possibly more suitable for low-cost fabrication compared to conventional approach (moisture and temperature controlled spin-coating or dipping coating method by Langmuir-Blodgett trough). In RIE process, the surface texturing was etched with various shapes to reduce the reflectivity from surface, and the spectral response measurement confirms the effectiveness of RIE texturing which showed phenomenal anti-reflection effect with less than 2% of light reflection below 1.0 um wavelength. In addition, experiments for Quinhydrone/Methanol (QHY/ME) surface passivation for RIE textured surface were proceeded to evaluate RIE texturing effect for surface recombination velocity and minority carrier lifetime.