DFT simulation of the Raman spectrum of single layer graphene

Abstract

Raman spectroscopy is one of the most suitable tools for studying few-layer graphene. The position of the G band and the defect-induced D and D' bands in the spectra of perfect single-layer graphene with sp2-hybridized carbon atoms and hydrogenated graphene with 27.7% sp3-hybridized carbon atoms are simulated using the Density Functional Theory (DFT) method with Perdew-Burke-Ernzerhof (PBE) functional. In the case of perfect graphene, the Raman G band is predicted at 1612 cm-1. In the case of the hydrogenated structure, a new feature appears. Namely, along with the G band, now shifted to 1591 cm-1, an additional feature, located at 1703 cm-1, is clearly seen. The latter is due to oscillations, involving six atomic benzene rings, containing two sp3-hybridized C atoms. According to our results, the presence of defects, related to sp3 hybridized carbon, gives rise to the appearance of the defect D' band in the Raman spectrum of defective graphene. This study shows that it is possible to simulate Raman spectra using the DFT method, with the results qualitatively matching the experimental data.