Adsorption-controlled Growth of Homoepitaxial c-plane Sapphire Films

TL;DR

This paper demonstrates a method for growing high-quality, atomically smooth homoepitaxial c-plane sapphire films with superior purity and optical properties, addressing key challenges in sapphire thin-film deposition.

Contribution

It introduces an adsorption-controlled growth process for sapphire that yields films with exceptional crystallinity, purity, and optical characteristics, advancing epitaxial sapphire fabrication.

Findings

Films are atomically smooth and highly crystalline.

Chemical purity of films exceeds substrate purity.

Films exhibit a single-crystal-like bandgap and low F+ center density.

Abstract

Sapphire is a technologically highly relevant material, but it poses many challenges to performing epitaxial thin-film deposition. We have identified and applied the conditions for adsorption-controlled homoepitaxial growth of c-plane sapphire. The films thus grown are atomically smooth, have a controlled termination, and are of outstanding crystallinity. Their chemical purity exceeds that of the substrates. The films exhibit exceptional optical properties such as a single-crystal-like bandgap and a low density of F+ centers.