Solar Cell Using Hourglass-Shaped Silicon Nanowires for Increased Light-Trapping Path
Myunghae Seo, Sol Yoon, Hyeonsu Cho, Seungho Lee, Ki‐Hyun Kim, Byoung Don Kong, M. Meyyappan, Chang‐Ki Baek
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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</sub> ) and 1.85 times higher efficiency with only simple diameter variations.