Controlled van der Waals heteroepitaxy of InAs nanowires on carbon honeycomb lattices.

We report on unconventional, noncovalent heteroepitaxy of vertical indium arsenide (InAs) nanowires on thin graphitic films in terms of van der Waals (VDW) interactions. Nearly coherent in-plane lattice matching (misfit of 0.49%) between InAs and the graphitic surface plays a critical role in the epitaxial formation of vertical InAs nanowires on graphitic substrates. Otherwise, gallium arsenide (misfit of -6.22%) is grown to be island morphologies. Cross-sectional transmission electron microscopy analyses show that 1-2 monomolecular layer ledges or kinks facilitate heterogeneous nucleation of InAs on nonwetting graphitic surfaces, forming the nuclei and promoting the subsequent nanowire growth with strong VDW interactions at the heterojunction. We further demonstrate the controlled VDW epitaxy method for high-yield and uniform InAs nanowire arrays on honeycomb carbon surface utilizing substrate surface etching and patterning techniques. Our work opens a new platform for the III-arsenide/graphene hybrid junction electronics and optoelectronics.