Graphene assisted III-V layer epitaxy for transferable solar cells

Abstract

Transferable III-V thin films, combined with light trapping structures, present several interests for photovoltaics: cost, material usage and weight reduction, flexible devices… To obtain such films, remote epitaxy consists in growing above a graphene covered III-V substrate, providing detachable mono-crystals. We report the fabrication of large-area graphene/GaAs substrates by a metal-assisted dry transfer with a high yield (<95%), reduced damage to the lattice, negligible doping, and stress relaxation. After the optimization of chemical etching steps, XPS reveals a residue-free surface with low oxidation levels compared to conventional transfers. Nucleation studies using MBE resulted in the formation of microcrystals, with partial alignment with the underlying GaAs(001).