University of Electronic Science and Technology of China
Investigation on the “Uncontrollable” Factors for Graphene Synthesis
State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Microelectronics and Solid State Electronics, University of Electronic Science and Technology of China, Chengdu, 610054, China
Graphene as one of the most promising materials has garnered tremendous attention because of its distinctive band structure and physical properties over the last decade. To date, synthesis of graphene by chemical vapor deposition (CVD) of hydrocarbons, particularly on Cu substrate, exhibits great potential as a cost-effective way to produce high-quality and large-area graphene films and various CVD methods have been explored such as hot/cold-wall CVD, low-pressure/atmosphere-pressure (LP/AP) CVD, gas/liquid/solid carbon feedstocks, etc.1-2In most of the scientific reports, researchers assumed the experiments were performed ideally with less discussion on the practical conditions such as impurities in gases and substrates, system contamination, and so on. Here I am going to present our investigation on two “uncontrollable” factors for graphene synthesis. One is the carbon contamination which may cause graphene nucleation and growth even without deliberately introducing carbon feedstock, which may result in defective graphene growth and high nucleation density. Another is the oxidative impurities induced due to system aging. We identified the source of these “uncontrollable” factors and proposed how to control them. Our workmay provide an explanation for the discrepancies among systems from different research groups. Understanding and thus controlling the “uncontrollable” factors are also of great importance to improve the system reliability, which is essential to achieve industrial mass production of graphene with excellent uniformity and reproducibility.
1. Li, X.; Cai, W.; An, J.; Kim, S.; Nah, J.; Yang, D.; Piner, R.; Velamakanni, A.; Jung, I.; Tutuc, E.; Banerjee, S. K.; Colombo, L.; Ruoff, R. S. Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils. Science 2009,324 (5932), 1312-1314.
2. Li, X.; Colombo, L.; Ruoff, R. S. Adv. Mater. 2016.
Dr. Xuesong Li is the inventor of the method of synthesis of large-area graphene films on Cu foils by chemical vapor deposition of methane. He got his B.S. and M.S. from Tsinghua University in 2000 and 2003, respectively and his Ph.D. from Rensselaer Polytechnic Institute in US in 2007. From May 2007 to Jan. 2012 Dr. Li pursued his post doctorate research in UT Austin and IBM T. J. Watson Research Center, respectively. In Feb. 2012, Dr. Li, together with his colleagues, co-founded Bluestone Global Tech, a company on graphene commercialization, and then LasLumin LLC in Jun. 2014. Dr. Li was awarded the 11th China 1000-talent plan (young-talent) and joined University of Electronic Science and Technology of China in 2015 as a professor. Dr. Li’s research interests are synthesis and applications of carbon nanomaterials such as carbon nanotubes and graphene. He has published 47 papers in peer reviewed journals such as Science, Nature Nanotechnology, Nature Materials, Nature Photonics, etc. with total citations over 15000, including 14 ESI highly-cited papers. His research work has been widely reported by multi-media such as BBC news, Nature, ScienceDaily, C&EN, etc. His work on graphene synthesis by chemical vapor deposition of methane on copper foil substrate, which was published in Science in 2009, was selected as one of the breakthroughs in 2009 by Science and has been cited over 5000 times. This invention has been widely used in both academy and industry up to date for graphene film production.