Mobility Extraction and Quantum Capacitance Impact in High Performance Graphene Field-effect Transistor Devices

TL;DR

This paper investigates the field-effect mobility in graphene transistors, emphasizing the importance of considering channel length dependence and quantum capacitance effects, and reports a ballistic mean free path of 300nm at room temperature.

Contribution

It introduces a method to accurately extract graphene's ballistic mean free path by incorporating electrical and channel length data, and presents the first quantum capacitance measurements on single-layer graphene.

Findings

Ballistic mean free path of 300nm at room temperature.

Substantial series resistance of around 300 ohms.

First quantum capacitance measurements on single-layer graphene.

Abstract

The field-effect mobility of graphene devices is discussed. We argue that the graphene ballistic mean free path can only be extracted by taking into account both, the electrical characteristics and the channel length dependent mobility. In doing so we find a ballistic mean free path of 300nm at room-temperature for a carrier concentration of ~1e12/cm2 and that a substantial series resistance of around 300ohmum has to be taken into account. Furthermore, we demonstrate first quantum capacitance measurements on single-layer graphene devices.