Molecular beam epitaxy growth of SrO buffer layers on graphite and graphene for the integration of complex oxides

•SrO films grown on graphene and graphite exhibit (001) orientation.•Smooth, pinhole-free SrO films on graphene and graphite are achieved.•The Dirac point electronic structure of graphene is maintained with SrO overlayers.•SrTiO3 films are grown atop the SrO buffer layers for oxide integration.

We report the successful growth of high-quality SrO films on highly-ordered pyrolytic graphite (HOPG) and single-layer graphene by molecular beam epitaxy. The SrO layers have (001) orientation as confirmed by X-ray diffraction (XRD) while atomic force microscopy measurements show continuous pinhole-free films having rms surface roughness of <1.5 Å. Transport measurements of exfoliated graphene after SrO deposition show a strong dependence between the Dirac point and Sr oxidation. Subsequently, the SrO is leveraged as a buffer layer for more complex oxide integration via the demonstration of (001) oriented SrTiO3 grown atop a SrO/HOPG stack.