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O: Fachverband Oberflächenphysik

O 109: Focus Session: Proximity Effects in Epitaxial Graphene II

O 109.4: Talk

Friday, March 22, 2024, 11:30–11:45, MA 141

Growth optimization and comparison of PASG epitaxial graphene on 4H- and 6H-SiC — •Teresa Tschirner, Yefei Yin, Klaus Pierz, Frank Hohls, and Hans Werner Schumacher — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

Fabricating epitaxial graphene by polymer-assisted sublimation growth (PASG) on SiC offers various advantages for application, such as production of large-area ultra-smooth defect- and bilayer-free graphene sheets, as well as reliable reproducibility. With the PASG method, the early formation of a buffer layer stabilizes the SiC surface and prevents step bunching of unfavorably high SiC surface terrace steps. We compare graphene growth on different polytypes of SiC with different parameters (such as miscut, polymer concentration, etc.) and the influence on the electronic properties of graphene. Differences between 4H- and 6H-SiC growth are two and three different terrace types, respectively, having inequivalent surface energies and subsequently different surface decomposition velocities [1]. We observe different step patterns on 6H-SiC of either alternating 0.25 and 0.5 nm high terrace-steps with alternating surface potential or equally distributed 0.75 nm steps. 4H-SiC on the other hand results for optimal growth in equally distributed very low step heights of 0.5 nm and equivalent SiC terraces with equal surface potential. The impact on the electronic transport is investigated by magneto-transport measurements.

[1] D. Momeni et al., Adv. Funct. Mater. 30, 2004695 (2020)

Keywords: epitaxial graphene; hexagonal silicon carbides; graphene buffer layer; surface-dependent polarization doping