Solar Cell Using Hourglass-Shaped Silicon Nanowires for Increased Light-Trapping Path

Abstract

Silicon nanowires (SiNWs) are promising structures with excellent photovoltaic properties for low-cost, high-efficiency solar cells and have the potential to overcome the limits of bulk silicon solar cells. There is still a need to enhance light absorption in SiNWs without increasing the surface area. Here, we introduce a novel design, hourglass-shaped silicon nanowire (HG-SiNW) to significantly increase the light-trapping path. Electrical and optical measurements show the superiority of HG-SiNW as an antireflective layer. In addition, whispering gallery mode identified by optical simulations accounts for the greatly improved absorption at the broadband solar spectrum. The HG-SiNW solar cells show an increase in short-circuit current (J(SC)) and 1.85 times higher efficiency with only simple diameter variations.