Semiconductor epitaxy on two-dimensional materials is beneficial for transferrable and flexible device applications. Graphene, due to the absence of permanent electric dipoles, cannot screen the electric field coming from the opposite side surface, allowing remote epitaxy for heteroepitaxy. This study demonstrates remote heteroepitaxy of ZnO microrods (MRs) on the GaN substrate across graphene layers via hydrothermal growth. Even the use of tri-layer graphene yields the remote heteroepitaxial MR arrays. Transmission electron microscopy reveals the remote heteroepitaxial relation between ZnO MRs and the GaN substrate despite the existence of graphene interlayers in between them. Density-functional theory calculations show that charge transfer along the z-direction at graphene/c-GaN possibly attract adatoms leading to remote heteroepitaxy, implying the field permeability of graphene. The ability of graphene to be released from the host substrate is exploited to exfoliate the overlayer MRs and regenerate the substrate.
Bibliographical noteFunding Information:
This research was financially supported by the Basic Science Research Program (Nos. NRF-2016R1D1A1B03931518 and 2010-0020207) and Global Research and Development Center Program (2018K1A4A3A01064272) through the NRF of Korea. The authors gratefully acknowledge financial support of the KIAT through the International Cooperative R&D program (N0001819). This work was supported by Laboratory Directed Research and Development and CINT, a U.S. Department of Energy, office of Basic Energy Sciences User Facility at Los Alamos National Laboratory (Contract No. DE-AC52-06NA25396) and Sandia National Laboratories (Contract No. DE-AC04-94AL85000).
© 2018 Author(s).