| Abstract: | Coaxial gallium arsenide single‐nanowire solar cells with multiple electrically and optically functional nanoshells are presented in this paper. Both optical absorption and light‐conversion characteristics are extensively examined by performing a comprehensive device‐oriented simulation. It is found that a window layer with a large semiconductor bandgap is necessary for the nanowire gallium arsenide solar cells, which allow internal quantum efficiency ~100% in ~75% of the absorption band of gallium arsenide. Results also reveal the role of nanofocusing effect in enhancing the performance of nanowire devices that show both absorption and external quantum efficiencies over 100% under resonances. A dielectric cladding shell is introduced and optimized, which enhances the nanofocusing effect and leads to extraordinary enhancement of both absorption and light‐conversion capabilities in a very broad band. This design contributes a short‐circuit current density increased by 2.4 times and an open‐circuit voltage over 1.1 V. Copyright © 2014 John Wiley & Sons, Ltd. |
