Maybe you dont have gaphene. even for amorphous carbon where you get very low 2D peak, but still should get G peak. U can check EDS to check if there is any C at all. if yes and u can make thick film then u can try XRD to check Gr signature. With the combination of Raman, EDS & XRD you can deffinitely predict whats going on..

Can you show a spectrum? Only a 2D peak could be interesting.

That could be a amorphous carbon bunch, though u can get minor peak of G and D. U can try XRD.

Hallo, I also got results for graphene oxide and rGO but i got only 2D band in all sample results with FT Raman spectra. I am confused .

That's not GO or RGO. It is amorphous carbon.

Exactly, just some C-H vibrations not sp2 carbon.