Optical and electrical characteristics of asymmetric nanowire solar cells

Abstract

We propose an asymmetric radial structure developed via simulation that improves the optical and electrical characteristics of silicon nanowire (SiNW) solar cells. This nanostructure is designed by shrinking the bottom core diameter and holding the top core diameter fixed in the SiNW, which results in a total reflection of the incident light in the outer wall of the shell due to the difference in the refractive index. The reflection enhances light trapping and concentration, which results in a 10 times higher optical generation rate and greater optical absorption in the high energy regime as compared with the fundamental symmetric radial structure. Further, we found that the efficiency is increased by over 10% when the bottom core diameter is decreased. The proposed structure has great potential to effectively improve the efficiency in concert with optimizing the design parameters. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3699212]