Dear Shamsudin,

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.

Please read https://www.physics.purdue.edu/quantum/files/Raman_Spectroscopy_of_Graphene_NOVA_Childres.pdf. The G*-band is called 2D here.

Dear Shamsudin,

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.

I agree with Subash Kore's observations; nothing more to add.

Hi,

D' peak (1620 1/cm) is like D peak (1350 1/cm) defect induced modes. and has A (1g) symm. It's not become from the splitting of the G mode.

what happen if only D band appeared BUT no G band

Only D - band may not possible in carbon allotrope materials.

https://www.researchgate.net/publication/279189527_Overtone_and_combination_features_of_G_and_D_peaks_in_resonance_Raman_spectroscopy_of_the_C78H26_polycyclic_aromatic_hydrocarbon

What will be the indication if 2D peak not found in rGO?

2D is the next most intense peak after G peak and it is seen even in the absence of defects. So, it must be present in the spectra of rGO. Moreover, rGO is similar in most of the properties to pristine graphene so its intensity ratio to G peak intensity will give info regarding the no. of layers.

This link is really useful,

http://www.instanano.com/characterization/experimental/raman-graphene/

If there is only one sharp Peak at arounf 1333 then it is for Diamond.

Strictly speaking it is not D Peak. D Peak is at 1350 which corresponds to distortion of Sp2 Crystal structure. Often People tend to confuse as these Peaks are close enough.

This link is really useful,

http://www.instanano.com/characterization/experimental/raman-graphene/

Please I need help

I am preparing Fe-Mn/rGO

When I did the raman for rGO it was good as seen in attached photo and there are clear distinctive D and G bands

But when I did the raman for FeMn/rGO the peaks were very strange, I cant' even say if the peak at ABOUT 1100 is a D or G band?

Please I would like to know your opinions

@AL-Hassan Mohammed Nasser

It seems like you are getting a lot of Plasmonic peaks from your Fe-Mn metals in Fe-Mn/rGo sample. Signals from you rGO may be all suppressed by high intensity Fe-Mn metal plasmonic peaks. Try lowering the loading or concentration of Fe-Mn on rGO and measure again. Make a sample with lowest Fe-Mn loading and lowest Fe-Mn particle size and try again. Let me know if it works. Good luck...

this peak around 1100 is for sure not D nor G rGO lines , there positions should not change . Mr Chandan has probably right

Please help me answer a question: how can we increase the intensity of 2D peak of monolayer graphene.

because i measured my graphene sheet at 532nm which is similar to that of a paper. while my sample reached the 2D peak intensity of 16000, the paper showed its result in 300, even though both of them are monolayer. from that, I knew that I synthesized the higher quality graphene. I am confused whether the intensity value is important or not ? or we just only get the ratio of 2D/G that is larger than 2 and the FWHM is around 30 for Si/SiO2 substrate.

many thanks!!!!

Hello Huynh,

The intensity of the 2D peaks or G peak is not at all considered. If you are trying to find the number of layers of Graphene, you need to find the relative intensity ratios of the 2D/G. The relative intensity ratios is nothing but the area under the curves 2D and G, which you get by plotting it. The relative intensity ratios 2D/G can be used to determine the number layers of Graphene. The intensity of the 2D peak varies will vary with your sample. So you may not worry about the values of the peaks.

Hi Shamsudin,

G-band refers to the garphene (Sp2) , D-band disorder structure of graphene and G*-band is radial breathing mode (all of the carbon atoms in a CNT move in the radial direction synchronously, which generates an effect similar to “breathing'' This mode is unique to CNTs, and is not observed in other carbon systems.

This book seems very useful in studying about graphene

Nazarpour S, Waite SR (2016) Graphene Technology: From Laboratory to Fabrication. Wiley- VCH, Germany.

Unlike the D peak, 2D ban d appears even in the absence of defect or impurities, which is suggest the highly order crystalline graphite carbon. The reason for 2D band is due to double resonance transition resulting from generation of two opposite phonon momentum.

The arise or disappearance of 2D band depends on the number of layer graphite stricture. The ratio 2D/G band gives the vital information about the number of layer graphitic carbon.

If ratio of 2D/G band is 2 than single layer-structure

if ratio is in between the 1-2 than bilayer or double layer

if ratio is in between the 1>0.5>0 than multilyer or double layer

Thanks

Regards

Gaurav

Can You give references, Gaurav?

Dear sir Eugene F Kislyakov

Sir I have attached the file here.

Thank You.

1350 cm-1 Disordered Carbon

1580 cm-1 and above Carbon Whiskers, Graphite Form

Regards

D peak around 1350 cm-1 is referred to disordered carbon structure.

G peak around 1580 cm-1 is referred to graphitic structure or whiskers like carbon

2D-band is referred to the stacking order of graphene layers.

G peak (1580 cm-1) is related to E2g phonon mode at the Brillouin zone center

The 2D peak (2700 cm-1) is related to the second order of zone boundary phonons (2700 cm-1)

And finally, the D peak (1350 cm-1) is related to the defect of the crystal

Regards

Hi all,

Eugene F Kislyakov, kindly refere to the following references, enough information about D G and 2D(G') are provided.

Cheers,

Thank You, Patrick.