Theoretical analysis and modeling of light trapping in high efficicency GaAs nanowire array solar cells

A rigorous analysis and design of efficient light trapping for Gallium arsenide nanowire array (NWA) solar cells is presented. The influence of the geometric parameters on the optical absorption of NWA has been thoroughly analyzed by using finite-difference time-domain simulations. It is found that the NWA have superior absorption characteristic over thin-film due to the combined effects of intrinsic anti-reflection and efficient excitation of resonant modes. Optimized optical designs arc obtained by maximizing the ultimate photocurrent under AM1.5G illumination. The photogeneration profiles under optimized conditions are incorporated into electrical modeling, in which the core-shell NWA solar cells exhibit 22.3% efficiency. (C) 2011 American Institute of Physics [doi:10.1063/1.3647847]