Pressure induced 3D strain in 2D Graphene

TL;DR

This study introduces a novel method to measure the transport properties of high-quality monolayer graphene under pressures up to 40 GPa, revealing its high out-of-plane stiffness and stable resistance, enabling large biaxial strains.

Contribution

A new technique for direct transport measurements of CVD graphene under high pressure up to 40 GPa is developed and demonstrated.

Findings

Graphene exhibits an out-of-plane stiffness of 0.26 GPa.

Resistances of graphene remain relatively constant under high pressure.

High pressure can induce large biaxial strains in graphene.

Abstract

Two-dimensional (2D) materials such as graphene offer a variety of outstanding properties for a wide range of applications. Their transport properties in particular present a rich field of study. However, the studies of transport properties of graphene under pressure are mostly limited to $\sim$1 GPa, largely due to the technical challenges and difficulties of placing graphene inside a diamond anvil cell (DAC) and maintaining good electrical contacts under pressure. We developed a novel technique allowing for direct measurements of the transport properties of high quality chemical vapor deposition (CVD) monolayer graphene under pressures. Combined Raman spectroscopic and direct resistivity measurements on pure monolayer graphene up to 40 GPa shows an effective out of plane stiffness of $c_{33}$=0.26$\pm_{.09}^{.11}$ GPa, and observe relatively constant resistances with pressure, suggesting high pressure as a useful technique for producing large biaxial strains within graphene.