I have synthesized RGO/ZnO/Cu composite and did Raman of that. I have got mainly 2 high intensity peaks. One is around 450 and another is around 1090cm-1. From the literature I came to know that 450cm-1 peak is of ZnO. But I'm confuse about the peak at 1090cm-1. D and G band of Graphene are around 1300 and 1500cm-1 respectively. Then why I'm getting only one peak at 1090?