Experimental observation of a suspended single layer graphene film on Cu foil grown via chemical vapor deposition method

The authors present the blue-shift of Raman 2D and G peak of a single layer graphene film, which is fabricated via chemical vapor deposition, on the relatively even Cu foil domain with nearly uniform thickness. This can be interpreted that rather mechanically compressive strain is exerted between graphene and the even Cu domain compared to the uneven. We observe that relaxing compressive strain to minimize the perturbation from Cu surface to the graphene film by virtue of the uneven Cu domain has a critical role in forming a suspended graphene. Furthermore, mechanical strain influence derived from the underlying substrate morphology can be suggested as one of the crucial elements in evaluating high quality graphene film considering suspended shape.