Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 41: Graphene: Growth, Substrate Interaction, Intercalation, and Doping
O 41.4: Talk
Wednesday, September 7, 2022, 11:15–11:30, S052
Properties of epitaxial graphene on various SiC terminations and polytypes investigated by low-energy electron microscopy — •Philip Schädlich1,2, Davood Momeni Pakdehi3, Florian Speck1,2, Klaus Pierz3, and Thomas Seyller1,2 — 1Technische Universität Chemnitz, Chemnitz, Germany — 2Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz, Germany — 3Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
The epitaxial growth of graphene on SiC has been improved from UHV growth to ambient pressure synthesis [1], and recently to the polymer-assisted sublimation growth (PASG) [2]. It results in an enhanced nucleation of the buffer layer and suppressed step bunching, which usually occurs upon the graphene formation by sublimation. Thus, PASG leads to homogeneous monolayer graphene with minimum step size equivalent to one or two SiC-bilayers. As a result of the latter, graphene on various surface terminations of the SiC substrate can now be systematically studied.
We utilize low-energy electron microscopy (LEEM) to identify the underlying substrate structure and to elucidate its delicate impact on the characteristic I(V) curves for different SiC polytypes. In addition, we investigate how the decoupling of the buffer layer from the substrate by hydrogen intercalation [3] influences the aforementioned effects.
[1] K. V. Emtsev et al., Nat. Mat. 8, 203 (2009). [2] M. Kruskopf et al., 2D Mater. 3 (4), 041002 (2016). [3] C. Riedl et al., PRL 103, 246804 (2009).