SiOC-Accelerated Graphene Grown on SiO 2 /Si with Tunable Electronic Properties Paul D. Garman, Hao Yang, Ying-Chieh Yen, Jianfeng Yu, Kwang Joo Kwak, Veysi Malkoc, Vishank V. Talesara, Ly J. Lee,* and Wu Lu* A facile method is developed for fast and high-coverage graphene growth on silicon wafers with covalent bonding by using atmospheric pressure chemical vapor deposition (APCVD) with methane as the carbon source and high temperature silicone rubber as the silicon oxycarbide (SiOC) source. The SiOC transition layer can facilitate and accelerate the formation of graphene. The formation of graphene networks with strong covalent bonding provides a combination of unique properties including higher mechanical strength and lower friction coefficient than a silicon wafer, excellent electrical conductivity, and high carrier mobility up to 275 cm 2 V 1 s 1 . Graphene is of particular interests due to its unique 2-D features among the carbon allotropes. [1] The hexagonal structure of carbon atoms within the 2-D graphene nanosheets gives rise to exceptional electrical conductivity, high thermal conductivity, large surface areas, strong mechanical properties, low friction coefficient, and excellent corrosion resistance. [2–4] Several strategies have been reported for manufacturing graphene for practical applications, including chemical or thermal exfoliation of graphite oxide, [4–6] epitaxial growth, [7] mechanical cleavage, [8,9] and chemical vapor deposition (CVD). [9,10] Metal-catalyzed CVD of graphene growth on copper and nickel foils has been proven to be one of the most promising strategies for large-scale synthesis and growth of thin graphene films. [11,12] However, the graphene film on copper or nickel has to undergo several processes to be transferred onto a silicon wafer substrate for electronic and display applications. [12] Ideally if graphene is grown on Si wafers with SiO 2 gate dielectric on the surface, back-gated field effect transistors (FETs) can be readily fabricated. CVD growth methods have been reported by several groups to grow graphene directly on Si substrates. [13–21] A mobility of 530 cm 2 V 1 s 1 has been demonstrated on SiO 2 /Si substrates. [17] However, the growth of graphene turned out to be very slow with poor surface coverage. Furthermore, the lack of atomic bonding between the graphene and the substrate made the graphene mechanically unstable on the substrate, which limits its potential appli- cations only to those where mechanical stresses are not a concern. In our previous study, we developed a facile method by floating atom-thick graphene nanosheets from a graphene nanopaper to form covalently bonded graphene crosslinking networks on various solid substrates in a vacuum furnace. [3] However, the graphene nanopapers are very expensive and the efficacy of graphene coating is low, i.e., <1% of graphene nanosheets on the nanopaper were transferred to the network on the substrate. Herein, we describe a simple and low-cost method for fast and high-coverage graphene growth on SiO 2 /Si substrates with covalent bonding by using atmospheric pressure CVD (APCVD) with methane as the carbon source and high temperature silicone rubber as the SiOC source. We found that the SiOC radicals which deposited as a transition layer on the silicon wafer surface from pyrolysis of the SiOC source could both facilitate and accelerate graphene growth and lead to the formation of graphene networks. This provides a new route of producing a strong and better covered graphene film on a silicon wafer without the use of a metal catalyst. The morphology and chemical structure of the SiOC-accelerated graphene networks can be tailored by varying the process conditions to alter its surface quality, mechanical strength, electrical conductivity, and carrier mobility. For a typical reaction, a 25  25  0.5 mm 3 thick silicon wafer covered by thermally grown silicon oxide and a certain amount of silicone rubber were placed inside a quartz tube (50 mm diameter and 600 mm long) under 50 SCCM argon flow. Approximately 10 min later, the temperature was increased from room temperature to 1000  C at 10  C min 1 . Then methane (15 SCCM), argon (50 SCCM), and hydrogen (0–20 SCCM) were applied for a desired reaction time. After the reaction, the quartz tube was cooled down to room temperature slowly before the coated silicon wafer was removed from the quartz tube. By changing the amount of silicone rubber added to the methane as well as the total reaction time and hydrogen flow, the coating thickness could be adjusted. Table S1, Supporting Information Dr. P. D. Garman, Dr. Y.‐C. Yen, Dr. J. Yu, Dr. K. J. Kwak, Dr. V. Malkoc, Prof. L. J. Lee Department of Chemical and Biomolecular Engineering The Ohio State University Columbus, OH 43210, USA E-mail: lee.31@osu.edu Dr. H. Yang, V. V. Talesara, Prof. W. Lu Department of Electrical and Computer Engineering The Ohio State University Columbus, OH 43210, USA E-mail: lu.173@osu.edu The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/pssr.201900017. DOI: 10.1002/pssr.201900017 graphene growth www.pss-rapid.com RAPID RESEARCH LETTER Phys. Status Solidi RRL 2019, 1900017 © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1900017 (1 of 5)