Raman Spectroscopy Study of Annealing-Induced Effects on Graphene Prepared by Micromechanical Exfoliation

TL;DR

This study uses Raman spectroscopy to analyze how annealing affects graphene prepared by micromechanical exfoliation, revealing contamination effects, Raman enhancement phenomena, and potential for selective molecular sensing.

Contribution

It demonstrates the impact of annealing on graphene contamination and Raman signals, highlighting the potential for selective molecular detection using graphene.

Findings

Contamination layers as thin as ~1 nm produce strong Raman bands.

Raman band intensity depends on excitation wavelength, indicating enhancement effects.

Graphene shows selective sensitivity to certain molecular species.

Abstract

In this note, we report a Raman spectroscopy study of annealing-induced effects on graphene samples prepared by the microexfoliation method. It was shown that randomly located adhesive residues often contaminate nearby graphene sheets during thermal annealing. The contamination on graphene can be as thin as ~1 nm, but gives several new Raman bands of unusually strong intensity. We also find that their intensity is strongly dependent on the excitation wavelength implying that graphene-induced Raman enhancement may be operative. The current study also suggests that graphene can be selectively sensitive towards certain molecular species in binding, which can be exploited for interesting application.