Work function tuning of metal/graphene stack electrode

Understanding of the contact between graphene and metal is a key issue to improve device performance. We extend the previous finding of work function pinning of monolayer graphene under various metals to multilayer graphene and discover that the work function of graphene under metal can be tuned from 4.3 eV to 5.1 eV by controlling the number of graphene layers. The work function of graphene is found to gradually shift with the number of graphene layers and four layers of graphene successfully screen this shift. These findings provide an alternative approach to control the work function of graphene electrodes.