Large Scale Graphene/H-Bn Heterostructures Obtained By Direct Cvd Growth Of Graphene Using High-Yield Proximity-Catalytic Process

We present a transfer-free process for the rapid growth of graphene on hexagonal boron nitride (h-BN) flakes via chemical vapor deposition. The growth of graphene on top of h-BN flakes is promoted by the adjacent copper catalyst. Full coverage of half-millimeter-sized h-BN crystals is demonstrated. The proximity of the copper catalyst ensures high-yield with a growth rate exceeding 2 mu m min(-1), which is orders of magnitude above what was previously reported on h-BN and approaches the growth rate on copper. Optical and electron microscopies along with Raman mapping indicates a two-step growth mechanism, leading to the h-BN being first covered by discontinuous graphitic species prior to the formation of a continuous graphene layer. Electron transport measurements confirm the presence of well-crystallized and continuous graphene, which exhibits a charge carrier mobility that reaches 2.0 x 10(4) cm(2) V-1 s(-1). Direct comparison of the mobility with graphene/h-BN devices obtained by wet transfer confirms an enhanced charge neutrality for the in situ grown structures.