Extraordinary high room-temperature carrier mobility in graphene-WSe$_2$ heterostructures

TL;DR

This paper demonstrates that graphene-WSe₂-hBN heterostructures exhibit unprecedented room-temperature carrier mobility exceeding previous materials by over three times, with implications for high-performance electronic and optoelectronic devices.

Contribution

The study introduces a novel heterostructure combining graphene, WSe₂, and hBN that achieves record-high room-temperature mobility surpassing existing van der Waals heterostructures.

Findings

Mobility up to 350,000 cm²/(Vs) at room temperature

Resistivity as low as 15 Ohm with weak temperature dependence

Modified acoustic phonon bands affecting electron-phonon scattering

Abstract

High carrier mobilities play a fundamental role for high-frequency electronics, integrated optoelectronics as well as for sensor and spintronic applications, where device performance is directly linked to the magnitude of the carrier mobility. Van der Waals heterostructures formed by graphene and hexagonal boron nitride (hBN) already outperform all known materials in terms of room temperature mobility. Here, we show that the mobility of today's best graphene/hBN devices can be surpassed by more than a factor of three by heterostructures formed by tungsten diselenide (WSe$_2$), graphene and hBN, which can have mobilities as high as 350,000 cm$^2$/(Vs) at room temperature, and resistivities as low as 15 Ohm. The resistivity of these devices shows a much weaker temperature dependence than the one of graphene on any other known substrate. The origin of this behaviour points to modified acoustic phonon bands in graphene and questions our understanding of electron-phonon scattering in van der Waals heterostructures.