Chemical Vapor Deposition Synthesis of Large-Area Graphene Films

Graphene films were synthesized with the method of chemical vapor deposition using gaseous methane as the source of carbon and copper foil as the substrate for the deposition. The following conditions were found optimal to grow large-area high quality graphene films: preliminary annealing of the foil in the argon/hydrogen mixture at 970-990 degrees C for 30-40 min; simultaneous supply of the argon/hydrogen mixture (100 cm(3)/min) and methane (10 cm(3)/min) for 5-10 minutes, and subsequent cooling in an inert atmosphere. As a result, 1-10 layered graphene films were obtained to fully coat the copper foil over the area up to 50 cm(2). Several methods have been developed to transfer graphene to dielectric substrates such as silicon oxide and flexible polymer films. The obtained graphene films were used to create a flexible transparent conductive touch panel and a highly sensitive resistive humidity sensor exhibiting fast response-recovery time.