GaAsP single nanowire solar cells grown on silicon exhibiting large Voc increase at multiple suns

A strong candidate to improve the cost/efficiency ratio of solar cells is a high efficiency dual-junction solar cell composed of a silicon bottom cell and a 1.7 eV direct bandgap III-V top cell. Monolithic integration of these two materials has proven difficult due to their different material properties which produce crystal defects and cause long term degradation. Here we present novel data on the first gold free gallium arsenide phosphide (GaAsP) nanowire solar cells with a 1.7 eV bandgap grown on silicon by means of direct epitaxial growth. The nanowires are grown containing a core-shell n-i-p junction and individual nanowires has an efficiency of up to 10.2% at 1-sun, and 11.5% at 10-suns.