Raman spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons

TL;DR

This study uses graphene bubbles and bilayer balloons to investigate the effects of biaxial strain on Raman spectra, confirming theoretical parameters and highlighting substrate interactions.

Contribution

It introduces a novel experimental approach using bubbles and balloons to analyze strain effects on graphene Raman spectra, minimizing substrate influence.

Findings

Gruneisen parameters match theoretical predictions

Substrate interactions cause discrepancies in previous measurements

Bilayer balloons effectively isolate strain effects

Abstract

In this letter we use graphene bubbles to study the Raman spectrum of graphene under biaxial (e.g. isotropic) strain. Our Gruneisen parameters are in excellent agreement with the theoretical values. Discrepancy in the previously reported values is attributed to the interaction of graphene with the substrate. Bilayer balloons (intentionally pressurized membranes) have been used to avoid the effect of the substrate and to study the dependence of strain on the inter-layer interactions.