Optical absorption in c-Si/a-Si:H core/shell nanowire arrays for photovoltaic applications

The optical properties have been numerically investigated in crystalline Si (c-Si)/hydrogenated amorphous Si (a-Si:H) core/shell nanowire (CSNW) arrays for various structural parameters. We have demonstrated that the light absorption can be greatly enhanced in c-Si/a-Si:H CSNW arrays especially for the weak absorption solar band (1.5-2.5 eV) of crystalline silicon nanowire (c-SiNW) arrays. We have also obtained the optimal parameters for photovoltaic applications, at which the photocurrent enhancement factors have been achieved to be 14% and 345% per volume material compared to in c-SiNW arrays and c-Si films, respectively. Furthermore, the underlying mechanism of the absorption enhancement in CSNW arrays has been discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615297]