A Surface-Plasmon-Enhanced Silicon Solar Cell With KOH-Etched Pyramid Structure

A pyramid structure etched with KOH solution was employed on a silicon (Si) surface to increase the absorbing path length of light; subsequently, gold (Au) nanoparticles (NPs) were deposited on the etched surface. Solar cells with and without KOH etching or Au NPs are fabricated to study the effects of KOH etching and Au NPs on the characteristics of solar cells. Due to the larger surface area etched by KOH, more Au NPs adhere to the Si surface, and hence more surface plasmon oscillations are induced by the incident light. For the incident wavelength longer than the oscillation wavelength of Au NPs (550 nm), constructive interference occurs, which enhances the short-circuit current density and conversion efficiency. In contrast, for a wavelength smaller than 550 nm, absorption dominates the extinction spectra. The short-circuit current density and conversion efficiency of the solar cells with KOH etching and Au NPs increase by 26.8% and 28.5%, respectively, compared with that of the solar cells without KOH etching and without Au NPs.