Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics

TL;DR

This paper reports the synthesis and characterization of ultrathin epitaxial graphite films exhibiting 2D electron gas behavior, demonstrating their potential for graphene-based nanoelectronics through patterning and gating techniques.

Contribution

It introduces a method to produce high-quality epitaxial graphene films with tunable electronic properties suitable for nanoelectronic device integration.

Findings

Observation of 2D electron gas behavior in epitaxial graphite

Demonstration of conductance modulation via top-gate

Potential for large-scale graphene nanoelectronics

Abstract

We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically 3 graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H-SiC, and characterized by surface-science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kOhm to 225 kOhm at 4 K, with positive magnetoconductance). Low resistance samples show characteristics of weak-localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 10^{12} cm^{-2} per graphene sheet. The most highly-ordered sample exhibits Shubnikov - de Haas oscillations which correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic techniques, and we demonstrate modulation of the film conductance using a top-gate electrode. These key elements suggest electronic device applications based on nano-patterned epitaxial graphene (NPEG), with the potential for large-scale integration.