Absorption enhancement of single silicon nanowire by tailoring rear metallic film for photovoltaic applications

In this work, single-nanowire solar cells (SCs) in lying configuration with a tunable rear metallic film are presented. Compared to the standalone silicon nanowire (SiNW), a significant/broadband enhancement in the overall optical absorption of the SiNW with rear metallic nanoconfiguration was observed. The optimized fraction, corresponding to the maximal ultimate photocurrent, of the SiNW surrounded by metallic film was achieved by properly engineering the SiNW radius and metallic film thickness. The considered configuration can be effectively extended to the alternative configuration with a SiNW partially embedded in a metallic substrate, where the ultimate photocurrent density of the 100 nm radius SiNW can be improved by 75.50% relative to that of the freestanding SiNW. Our simulations verify that it is a promising route for developing highly efficient single nanowire SCs. (C) 2014 Optical Society of America