Excellent Surface Passivation and Light Absorption in Crystalline Si via Low-Temperature Si Nanowire Growth

Abstract

Developing structures that provide excellent light absorption while keeping a high surface passivation quality is a mandatory issue for crystalline Si solar cells. In this study, Si nanowires grown on crystalline Si wafers using plasma-enhanced chemical vapor deposition (PECVD) are used as nanostructures for an efficient light absorption. Two types of stacks with direct or decoupled growth of nanowires on crystalline Si have been studied in order to identify their influence on the light absorption, as well as on the passivation quality. By choosing appropriately the stack configuration and carefully adjusting parameters such as silicon nitride thickness, Si nanowire diameters, and lengths, we have obtained an effective carrier lifetime up to 1.7 ms. Moreover, modeling has shown that a photogeneration density above 41 mA/cm2 can be expected in the c-Si wafer.