I am studying graphene growth by cvd. I want to find the number of graphene layers which I produced using Raman results. I researched some paper and I found that graphene layers could be calculated by lorentz peaks but I don't know how these peaks are calculated. Could you help me?
First of all, you can identify the layer/layers by color of optical image after transferring graphene onto SiO2/Si substrates. And deconvolute 2D or G' peak into multipeak by using software like ORIGIN in Lorentzian shape.
With addition FWHM of 2D peak is also measure of number of layers
Ref: http://www.sciencedirect.com/science/article/pii/S0370157309000520
C A R B ON 4 7 ( 2 0 0 9 ) 1 3 0 3 –1 3 1 0
If you are measuring graphene on copper there may be big problem with graphene band observation- Raman spectra graphene on copper are very weak. The other problem is graphene on copper is rearly monolayer and even monolayer is not always single Lorenzian.
In another case-if you are measuring graphene transferred on Si02 situation is much easier. Monolayer graphene may be easy found in every good optical microscope and than to calculate FWHM 2D you should use origin or some mathematical program. Fitting it "manualy" is not very easy.
Miss/Mrs Kasap, I am allowing to recommend you to use for the interpretation of the Raman spectra a mixed function. Lorenzian with contribution of the Gaussian one. If you try to apply this approach, than the chemometrics of the approximated curve is improved significantly. In this respect ORIGIN is not suitable software. Grams AI Spectroscopic software is more suitable (http://www.thermoscientific.com/en/select-country.html?comeFromUrl=%2Fen%2Fproduct%2Fgrams-ai-spectroscopy-software.html). Nevertheless that it is product of Thermo Fisher, it can proceed with spectroscopic data sets of all actually currently available in the market FT-Raman and FTIR spectrometers.
Dear Bojidarka,
Can you clear about the "chemometrics of the approximated curve"?
With addition, can you give the answer of following link
https://www.researchgate.net/post/Why_is_Lorentzian_fitting_needed_for_raman_spectra_of_graphene_2D_peak
Most of the literature suggesting to fit D, G , G' peak by lorentzian. Is there any relation between Lorentzian function with lineshape of D or G or G' peak? Or can you suggest any reference regarding that?
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