Dear Md.Akibul Islam ,

The D-mode is caused by disordered structure of graphene. The presence of disorder in sp2-hybridized carbon systems results in resonance Raman spectra, and thus makes Raman spectroscopy one of the most sensitive techniques to characterize disorder in sp2 carbon materials.

The G-mode is at about 1583 cm-1, and is due to E2g mode at the Γ-point. G-band arises from the stretching of the C-C bond in graphitic materials, and is common to all sp2 carbon systems.

If there are some randomly distributed impurities or surface charges in the graphene, the G-peak can split into two peaks, G-peak (1583 cm-1) and D’-peak (1620 cm-1). The main reason is that the localized vibrational modes of the impurities can interact with the extended phonon modes of graphene resulting in the observed splitting.

All kinds of sp2 carbon materials exhibit a strong peak in the range 2500 - 2800 cm-1 in the Raman spectra. Combined with the G-band, this spectrum is a Raman signature of graphitic sp2 materials and is called 2D(G*)-band. 2D-band is a second-order two-phonon process and exhibits a strong frequency dependence on the excitation laser energy.

****Apropos to your Question

You can get a detailed explanation of the different Raman contributions in Graphene in the work of Nicola Ferralis (https://arxiv.org/pdf/1005.4900.pdf) and in the paper of A.C. Ferrari:Article Interpretation of Raman Spectra of Disordered and Amorphous Carbon

were a detailed description of ID/IG ratio can be found.

Kind regards,

Md Osim,India

Dear Akibul,

Raman spectroscopy is employed in order to gain more scientific insight about crystal disorder and chemical modification due to functional groups.

Generally, Graphene layer shows the G (at ~1585 cm-1) band which shifts to left, this small left-shift is so-called blue-shift.

I hope this is the satisfactory answer.

Azhar Ali you are saying correct however, one thing more is that such shifting in Raman band is due to the presence of oxygen vacancies generated residual stresses created defects and micro-strains

Dear Md.Akibul Islam ,

The D-mode is caused by disordered structure of graphene. The presence of disorder in sp2-hybridized carbon systems results in resonance Raman spectra, and thus makes Raman spectroscopy one of the most sensitive techniques to characterize disorder in sp2 carbon materials.

The G-mode is at about 1583 cm-1, and is due to E2g mode at the Γ-point. G-band arises from the stretching of the C-C bond in graphitic materials, and is common to all sp2 carbon systems.

If there are some randomly distributed impurities or surface charges in the graphene, the G-peak can split into two peaks, G-peak (1583 cm-1) and D’-peak (1620 cm-1). The main reason is that the localized vibrational modes of the impurities can interact with the extended phonon modes of graphene resulting in the observed splitting.

All kinds of sp2 carbon materials exhibit a strong peak in the range 2500 - 2800 cm-1 in the Raman spectra. Combined with the G-band, this spectrum is a Raman signature of graphitic sp2 materials and is called 2D(G*)-band. 2D-band is a second-order two-phonon process and exhibits a strong frequency dependence on the excitation laser energy.

****Apropos to your Question

You can get a detailed explanation of the different Raman contributions in Graphene in the work of Nicola Ferralis (https://arxiv.org/pdf/1005.4900.pdf) and in the paper of A.C. Ferrari:Article Interpretation of Raman Spectra of Disordered and Amorphous Carbon

were a detailed description of ID/IG ratio can be found.

Kind regards,

Md Osim,India