Synthesis and Characterization of Atomic and Electronic Properties of Graphene Directly Grown on Dielectric Substrates
- Speaker: Prof. Young Jae Song (Sungkyunkwan Univ.)
- Date: Wednesday, October 18, 2017, at 17:00
- Place: Jungho Seminar
Electronic structures of graphene is affected by number of graphene layers, stacking order or substrates effects.[1,2] Control of layer numbers as well as scalability has been the main issues for device applications based on graphene. In addition, its electronic properties are changed uncontrollably while transferring it on to dielectric substrates for applications. New and unique CVD methods, therefore, are proposed to synthesize large-area and high-quality graphene by [1] an iterative process of graphene growth and h-BN etching or [2] replacing the growth substrate in chemical vapor deposition (CVD). A h-BN thin film is utilized to provide a gap of well-defined thickness for introducing the precursors and to play the role of the epitaxial growth of multilayer graphene. A thin h-BN film, initially-CVD grown on copper,[3] is locally etched out by hydrogen atoms decomposed from CH4 during the sequential graphene growth, which generates additional growth channels of graphene adlayers again under the first graphene layer. The crystallinity with AB stacking was confirmed by Raman analysis and selected-area electron diffraction measurements as well as statistical studies of optical microscope images. In the other method, an atomically thin and flat silica layer is utilized to offer a van der Waals epitaxy with a hexagonal lattice. This graphene directly grown on the dielectric substrate will be discussed further in detail in the presentation.
References
1. Castro Neto, A. H., Guinea, F., Peres, N. M. R., Novoselov, K. S. & Geim, A. K. The electronic properties of graphene. Rev. Mod. Phys. 81, 109–162 (2009).
2. Geim, A. K. & Novoselov, K. S. The rise of graphene. Nat. Mater. 6, 183–191 (2007).
3. Wang, M. et al. A Platform for Large-Scale Graphene Electronics - CVD Growth of Single-Layer Graphene on CVD-Grown Hexagonal Boron Nitride. Adv. Mater. 25, 2746–2752 (2013).