Synthesis of Isotopically-Labeled Graphite Films by Cold-Wall Chemical Vapor Deposition and Electronic Properties of Graphene Obtained from Such Films

摘要

We report the synthesis of isotopically-labeled graphite films on nickel substrates by using cold-wall chemical vapor deposition(CVD).During the synthesis,carbon from^(12)C-and^(13)C-methane was deposited on,and dissolved in,a nickel foil at high temperature,and a uniform graphite film was segregated from the nickel surface by cooling the sample to room temperature.Scanning and transmission electron microscopy,micro-Raman spectroscopy,and X-ray diffraction prove the presence of a graphite film.Monolayer graphene films obtained from such isotopically-labeled graphite films by mechanical methods have electron mobility values greater than 5000 cm^(2)·V^(-1)·s^(-1)at low temperatures.Furthermore,such films exhibit the half-integer quantum Hall effect over a wide temperature range from 2 K to 200 K,implying that the graphite grown by this cold-wall CVD approach has a quality as high as highly oriented pyrolytic graphite(HOPG).The results from transport measurements indicate that^(13)C-labeling does not significantly affect the electrical transport properties of graphene.