Vacancies effect on graphene: Raman study

Abstract

The acid oxidation treatment methods have been widely reported as an effective method to purify and functionalize the surface of graphene. Although effective, the strong acids typically employed may cause graphene extra-damage, limiting its potential. This work examines the use of a concentrated HNO3/H2SO4 mixture in dispersing graphene in aqueous sulfactant solutions. Raman spectroscopy can be used to provide a rapid and non-destructive analysis to estimate the concentration of defect created by acid in graphene. The X-ray diffraction (XRD) was used to compare the patterns as a function of the acid concentration used in thin films. The Raman measurements were performed on graphene deposited on Si substrates. The first-order resonance Raman scattering mechanisms in graphene with defects were analysed considering the origin of the G and D bands. In the other hand, the acid can probably creat the vacancies defects on grapheme. Then, we calculate Raman spectra of graphene with mono, di and tri-vacancies defects as function of the concentrations of such defects. The obtained results we observed that the D band appeared, the results are coherent and in agreement with the experimental analysis.