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.