Ballistic transport at room temperature in micrometer size multigraphene

TL;DR

This study demonstrates room-temperature ballistic transport in micrometer-sized multigraphene, revealing exceptionally high carrier mobility and mean free path, which are crucial for nanoelectronic applications.

Contribution

It provides the first direct measurement of intrinsic carrier mobility and mean free path in micrometer-sized multigraphene at room temperature.

Findings

Carrier mean free path is micrometer scale.

Carrier mobility is approximately 6 million cm²/Vs.

Carrier density per graphene layer is about 7×10^8 cm⁻².

Abstract

The intrinsic values of the carriers mobility and density of the graphene layers inside graphite, the well known structure built on these layers in the Bernal stacking configuration, are not well known mainly because most of the research was done in rather bulk samples where lattice defects hide their intrinsic values. By measuring the electrical resistance through microfabricated constrictions in micrometer small graphite flakes of a few tens of nanometers thickness we studied the ballistic behavior of the carriers. We found that the carriers' mean free path is micrometer large with a mobility $\mu \simeq 6 \times 10^6 $cm$^2$/Vs and a carrier density $n \simeq 7 \times 10^8 $cm$^{-2}$ per graphene layer at room temperature. These distinctive transport and ballistic properties have important implications for understanding the values obtained in single graphene and in graphite as well as for implementing this last in nanoelectronic devices.