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First-principles study on remote van der Waals epitaxy through graphene monolayer on semiconductor substrates


 To investigate the mechanism of remote epitaxy where the overlayer can follow the same crystalline structure as the underlying semiconductor substrate through thin two-dimensional interlayer, we systematically study the potential fluctuations of graphene covered Si, GaAs, and GaN substrates from first-principles. We find that the uneven semiconductor surface, the distorted graphene, and the non-uniform interface charge transfer have significant contributions to the potential fluctuation. Semiconductor substrate with different surface reconstructions and orientations would generate different potential fluctuations through graphene interlayer. Besides, we calculate and compare the adsorption of adatoms on graphene covered substrates. The adsorption energies of adatoms not only depend on their distances to the underlying semiconductor surface, but also are sensitive to the direction of the charge transfer at the graphene/substrate interface. Changing the semiconductor reconstruction or orientation could even reverse the order of the adsorption energies of cation and anion adatoms by reversing the interface charge transfer direction, leading to the change of growth orientation of the overlayer. Our study improves the understanding to the mechanism of remote epitaxy, and reveals the possibility to control the initial nucleation and orientation of overlayers by changing the semiconductor reconstructions and/or orientations in remote epitaxy.