报告题目：CVD Growth and Electrical Characterization of Single-Crystal Graphene and Its Bilayer
报 告 人：Dr. Yufeng Hao - Research Scientist in Columbia University
报告摘要：In this talk, I will present a few projects regarding one-dimensional (1-D) and 2-D material growth kinetics and electrical properties, which cover my research career during last ten years. In particular, I will discuss the detailed CVD growth kinetics of graphene and its bilayer, both of which are promising for electronics, photonics and energy harvesting applications: (1) oxygen (O) on the Cu growth substrates was found to substantially decrease the graphene nucleation density by passivating Cu surface active sites. Control of surface O enabled growth of centimeter-scale single-crystal graphene domains. O also accelerated graphene domain growth and shifted the resulting graphene domain shape from compact to dendritic. (2) A new growth mechanism was proposed that can control the Bernal-stacking order of two graphene layers, the synthesized single-crystal bilayer graphene domain can be as large as 500 micrometers. Electrical transport measurements also show outstanding carrier mobility over 60,000cm2v-1s-1 for both graphene and bilayer on hexagonal boron nitride device substrates. More interesting, we observed a bandgap ~100meV at a displacement field of 0.9V/nm in the bilayer graphene. Our works will meet the potentials of graphene in various applications.
Dr. Yufeng Hao obtained his B.S. and Ph.D degrees from Shanxi University (2001) and Institute of Solid State Physics, Chinese Academy of Sciences (2006), respectively. He worked as Postdoctoral fellow in National University of Singapore (2007-2010) and then in the University of Texas at Austin (2010-2014). Currently, he is a Research Scientist in Columbia University.
Dr. Hao’s research focuses on growth, characterization, and electrical device measurements of various low-dimensional materials and nanostructures. He has 4 Chinese and US patents, and gave more than 10 invited or contributed talks. Dr. Hao has published over 50 peer-reviewed journal papers, including Science, Nature, Physical Review Letters, etc. These papers have been cited more than 2200 times, and H-index is 27.