The carbon's solubility into copper is extremely reduced and so largely floor diffusion and nucleation of carbon atoms are involved. Because of this and also the growth kinetics, the graphene thickness is restricted to predominantly a monolayer. The massive edge is that the graphene might be grown on Cu foil https://www.facebook.com/permalink.php?story_fbid=pfbid02t5PjjArqP3gPPD1S5n8JHwaZEfNndEsPy9eGu73RNrHLmB7wxu7qmEiraP76ixvfl&id=61560512640678&__cft__[0]=AZWn3HyvOafh63eJ2nDvKcJyIW1z5KHvCQgJJTHSgYoA0uefOT4ooUmaTFW7mD1RVLYAEow_UW17A03TjYpPTyOcD0jq2eBd92YEP_uMHgx0iNNWDRbu4QGsY6sfsDsvtKQ4jqEr_OjlQfL3O59HZGwX3Gqp12O5AFF5aeMIAXZjuWk_YNpgzhUbQMAdCgzaJ-b9CHGNxErbt1TULb-uzf_M&__tn__=%2CO%2CP-R