Growth of graphene on non-catalytic substrate by controlling the vapor pressure of catalytic nickel

Abstract

Here, we demonstrate a simple method of growing graphene directly on various dielectric substrate using vapor-phase metal catalyst via mobile hot-wire (MHW) assisted chemical vapor deposition (CVD). The MHWmade of nickel (Ni) is utilized as an independent source of the metal vapor as well as a moving heat source. The hot-wire temperature (Tw, 800-1100 degrees C) and the total chamber pressure (P-tot, 0.1-760 torr) determine the equilibrium partial vapor pressure of nickel (P-Ni, similar to 10(-11) to similar to 10(-3) torr). When the equilibrium P-Ni is built in the chamber, reaction between Ni vapor and carbon feedstock in a gaseous phase results in deposition of carbon containing Ni particles on dielectric substrate. The optimum growth conditions for low-defect and uniform graphene are found at the substrate temperature (T-sub) of 700 degrees C and the speed of MHW (V-w) near 1.0 mm/min, which determines the nucleation and lateral growth of graphene from the deposited Ni particles. Consequently, the PNi was clarified as a primary factor for graphene grown on non-catalytic substrate (NCS) by comparing the graphene grown by solid and vaporphase metal catalyst. We believe the results contribute to the understanding of the direct-growth mechanism of graphene on NCS. (C) 2018 Elsevier Ltd. All rights reserved.