Background pressure does matter for the growth of graphene single crystal on copper foil: Key roles of oxygen partial pressure

Understanding the effect of minor elements such as oxygen and nitrogen on the growth of graphene is crucial to fabrication of graphene single crystals (GSC) with large grain size. In this study, we investigate the nucleation and growth behavior of graphene domains on commercial copper foils as a function of oxygen partial pressure in the chemical vapor deposition (CVD) chamber. To achieve repeatable fabrication of GSC, it is essential to backfill CVD chamber with moderate amount of oxygen during substrate annealing and graphene growth stages. In another words, the relatively higher background pressure in CVD chamber is beneficial to the fabrication of GSC. In addition to reducing the nucleation density of graphene grains, the backfilled oxygen induces (111) reconstruction of copper foil upon annealing at 1050 degrees C for 2 h. The oxygen-induced crystallinity of copper substrate should account for the growth of hexagonal-shaped GSC of millimeter-scale on commercial copper foil with single layer nature. (C) 2018 Elsevier Ltd. All rights reserved.