Diffusion-assisted molecular beam epitaxy of CuCrO$_2$ thin films

TL;DR

This paper introduces diffusion-assisted epitaxy, a novel growth mode for molecular beam epitaxy that enables high-quality CuCrO$_2$ film growth without precise flux control by leveraging excess species diffusion into the substrate.

Contribution

The study presents diffusion-assisted epitaxy as a new self-limited growth mode for MBE, simplifying stoichiometry control in multi-elemental oxide film growth.

Findings

High-quality CuCrO$_2$ films achieved over a wide growth window

Diffusion-assisted epitaxy reduces the need for precise flux control

Demonstrates a new approach to stoichiometry management in MBE

Abstract

Using molecular beam epitaxy (MBE) to grow multi-elemental oxides (MEO) is generally challenging, partly due to difficulty in stoichiometry control. Occasionally, if one of the elements is volatile at the growth temperature, stoichiometry control can be greatly simplified using adsorption-controlled growth mode. Otherwise, stoichiometry control remains one of the main hurdles to achieving high quality MEO film growths. Here, we report another kind of self-limited growth mode, dubbed diffusion-assisted epitaxy, in which excess species diffuses into the substrate and leads to the desired stoichiometry, in a manner similar to the conventional adsorption-controlled epitaxy. Specifically, we demonstrate that using diffusion-assisted epitaxy, high-quality epitaxial CuCrO$_2$ films can be grown over a wide growth window without precise flux control using MBE.