Free-Standing Epitaxial SrTiO$_3$ Nanomembranes via Remote Epitaxy using Hybrid Molecular Beam Epitaxy

TL;DR

This paper introduces a hybrid molecular beam epitaxy method to grow epitaxial complex oxide films on graphene without damage, enabling the creation of free-standing nano-membranes for advanced applications.

Contribution

The study presents a novel hybrid molecular beam epitaxy technique that grows complex oxides on graphene without damaging it, allowing for exfoliation and transfer of free-standing nano-membranes.

Findings

Epitaxial growth achieved without damaging graphene

Films exhibit self-regulating cation stoichiometry

Films can be exfoliated and transferred to other substrates

Abstract

The epitaxial growth of functional materials using a substrate with a graphene layer is a highly desirable method for improving structural quality and obtaining free-standing epitaxial nano-membranes for scientific study, applications, and economical reuse of substrates. However, the aggressive oxidizing conditions typically employed to grow epitaxial perovskite oxides can damage graphene. Here, we demonstrate a technique based on hybrid molecular beam epitaxy that does not require an independent oxygen source to achieve epitaxial growth of complex oxides without damaging the underlying graphene. The technique produces films with self-regulating cation stoichiometry control and epitaxial orientation to the oxide substrate. Furthermore, the films can be exfoliated and transferred to foreign substrates while leaving the graphene on the original substrate. These results open the door to future studies of previously unattainable free-standing nano-membranes grown in an adsorption-controlled manner by hybrid molecular beam epitaxy, and has potentially important implications for the commercial application of perovskite oxides in flexible electronics.