Improvement of Morphology and Free Carrier Mobility through Argon-Assisted Growth of Epitaxial Graphene on Silicon Carbide

TL;DR

This study demonstrates that argon-assisted epitaxial growth of graphene on silicon carbide improves film morphology and increases free carrier mobility, especially on the C-face, by reducing scattering and carrier density.

Contribution

It introduces argon atmosphere during growth as a method to enhance graphene quality and electrical properties on silicon carbide substrates.

Findings

Argon growth improves morphology on C-face but not on Si-face.

Carrier mobility increases with argon growth.

Sheet carrier density decreases with argon growth.

Abstract

Graphene was epitaxially grown on both the C- and Si-faces of 4H- and 6H-SiC(0001) under an argon atmosphere and under high vacuum conditions. Following growth, samples were imaged with Nomarski interference contrast and atomic force microscopies and it was found that growth under argon led to improved morphologies on the C-face films but the Si-face films were not significantly affected. Free carrier transport studies were conducted through Hall effect measurements, and carrier mobilities were found to increase and sheet carrier densities were found to decrease for those films grown under argon as compared to high vacuum conditions. The improved mobilities and concurrent decreases in sheet carrier densities suggest a decrease in scattering in the films grown under argon.