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

TL;DR

This paper demonstrates the successful growth of high-quality SrO buffer layers on graphite and graphene using molecular beam epitaxy, enabling integration of complex oxides like SrTiO3 with 2D materials.

Contribution

It introduces a method for growing oriented SrO films on graphite and graphene, facilitating complex oxide integration on 2D materials.

Findings

SrO films are (001) oriented with smooth, pinhole-free surfaces.

Transport measurements show a strong dependence of graphene's Dirac point on Sr oxidation.

SrTiO3 can be grown atop SrO/graphite stacks, demonstrating oxide integration.

Abstract

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 {\AA}. 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.