Room-temperature electric field effect and carrier-type inversion in graphene films

TL;DR

This paper demonstrates that thin monocrystalline graphite films exhibit a strong electric field effect at room temperature, allowing control over carrier type and concentration, with potential for electronic device applications.

Contribution

It introduces a new two-dimensional, high-quality graphite film system that can be controlled by electric field, enabling carrier-type inversion at room temperature.

Findings

Graphite films exhibit electric field-induced carrier-type inversion.

Films remain metallic and high-quality down to atomic thickness.

Room-temperature ballistic transport observed in the films.

Abstract

The ability to control electronic properties of a material by externally applied voltage is at the heart of modern electronics. In many cases, it is the so-called electric field effect that allows one to vary the carrier concentration in a semiconductor device and, consequently, change an electric current through it. As the semiconductor industry is nearing the limits of performance improvements for the current technologies dominated by silicon, there is a constant search for new, non-traditional materials whose properties can be controlled by electric field. Most notable examples of such materials developed recently are organic conductors [1], oxides near a superconducting or magnetic phase transition [2] and carbon nanotubes [3-5]. Here, we describe another system of this kind - thin monocrystalline films of graphite - which exhibits a pronounced electric field effect, such that carriers in the conductive channel can be turned into either electrons or holes. The films remain metallic, continuous and of high quality down to a few atomic layers in thickness. The demonstrated ease of preparing such films of nearly macroscopic sizes and of their processing by standard microfabrication techniques, combined with submicron-scale ballistic transport even at room temperature, offer a new two-dimensional system controllable by electric-field doping and provide a realistic promise of device applications.