shows the Raman spectra of GO, and graphene, . Both GO and graphene have a couple of Raman-active bands in the spectra, with the D band at 1350 cm-1 corresponding to defects or edge areas and G band at 1598 cm-1 related to the vibration of sp2 -hybridized carbon.

check this

https://sci-hub.se/10.1007/s11664-015-4212-8

Hi Mohamed Elsayed Harb sir, thank you for your response.

Sir, I am specifically asking about the significance of the four components usually observed in 2D band (~2650 cm-1) for graphene as mentioned in some scholarly articles. Yes you are right that the D band and G band corresponds to the defect order peak and graphitization peak in graphene.

Although, Graphene Oxide (GO) doesn't really exhibit 2D band in Raman spectroscopy due to the association of different functional groups to sp2 hybridized carbon atoms indicating that the GO is dominated by the fully-disordered sp2 bonding network. While 2D band is usually observed in pristine graphene film, only when the crystallinity of that graphene is high (with a few defects). Thus, GO and pristine graphene can be distinguished from this observation of 2D peak from Raman spectroscopy.

I am synthesizing graphene in ECR Plasma based CVD system (physical route) utilizing catalytic substrate with a view to obtain graphene in its pristine form. Hence, I am interested on the 2D band and its components (as seen in attachment).

In some literature, the role of transverse optical (TO) phonons around the K point of Brillouin zone and its activation by double resonance (DR) is stated without detailed explanation.

In this regard, any articles/ books/ lectures with detailed explanation related to the aforementioned will definitely improve the knowledge for better understanding.

It seems rather arbitrary to divide the peak into 4 sub-bands this way. It might be possible to fit it almost equally well with just 1 or 2 peaks.

I think you would be better of looking how the overall 2D band shifts or broadens across samples and associate that to bond strengths and expected vibration frequencies, rather than to get hung up on the precise number of peaks you happened to fit and assuming they are completely separate processes.

Manuel Schnabel sir, I totally agree with you. Although, I was reading the article of Gayathri et al. (AIP Advances 4, 027116 (2014)) and found out the image that has been shared.

While the 2D band in the shared image can be fitted with 1 or 2 peaks, but why authors have gone for 4 sub-bands that I cannot really follow. Even though the peaks have been fitted with 1 or 2 peaks, in that case, which sub-bands of 2D peak should one consider among 2D1A, 2D1B, 2D2A, 2D2B ?

Thank you Dr. Akhilesh Pandey