Growth of graphene on SiO2 with hexagonal boron nitride buffer layer

Abstract One-through process of graphene growth on insulator substrates with inserting a hexagonal boron nitride ( h -BN) buffer layer is expected to yield significant improvements in performance of electron transport properties of graphene devices due to the alleviation of the interface interaction between graphene and insulators and the enhancement of the flatness of the substrate. In this study, we successfully fabricated a graphene/ h -BN/SiO 2 heterostructure by direct chemical vapor deposition (CVD) without mechanical transfer processes. It was found that h -BN promotes the growth of graphene on SiO 2 whereas the graphene growth without the h -BN layer is extremely difficult. The electronic structures of graphene and h -BN were investigated by using micro-Raman spectroscopy and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The B and N K -edge NEXAFS revealed that substitutional oxygen impurities with the chemical form of BN 3- x O x , ( x = 1, 2, 3) are present in both h- BN/SiO 2 and graphene/ h -BN/SiO 2 . The number of O substitutional impurities is two times larger in graphene/ h -BN/SiO 2 than in h -BN/SiO 2 , which is presumed to be due to the reaction with oxygen from SiO 2 and methanol during the graphene growth. The interfacial interaction between graphene and h -BN was found to be weak in graphene/ h -BN/SiO 2 . The present study shows that the h -BN layer grown with CVD can be a superior buffer layer for graphene devices which enables direct graphene growth on it and to decrease the interactions with insulator substrates.