Enhanced Power Conversion Efficiency in Single Nanowire Devices through Symmetry Breaking Design

Semiconductor and dielectric nanostructures have highly tunable resonances that have been used to increase light absorption in a variety of photovoltaic and photodetector devices. In this article, we demonstrate that horizontally placed and partially capped nanowires (PCNWs) exhibit strongly enhanced light trapping than conventional bare and core shell nanowires. Based on the temporal coupled-mode theory, we analyze the coupling strength between incident light and leaky mode resonances as a function of the cap angles of the PCNWs. Compared with the conventional bare and core shell nanowires, the PCNWs support more hybrid leaky modes and therefore give rise more coupling channels. Significant increase in short-circuit current and noticeable increase in open-circuit voltage enable the PCNW to possess high power conversion efficiency of 55.31 %, increased by 42.7% and 141 %, respectively, compared with that of the conventional core-shell nanowire (38.76%) and bare nanowire (22.95%).