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O: Fachverband Oberflächenphysik

O 55: Graphene

O 55.6: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-EG

Preparation of epitaxial graphene on 4H-SiC(0001) — •Hassan Kakag, Florian Speck, Martina Wanke, and Thomas Seyller — Professur für Technische Physik, TU Chemnitz, Reichenhainer Str. 70, D-09126 Chemnitz, Germany

The growth of epitaxial graphene (EG) on 6H-SiC(0001) in argon under atmospheric pressure provides high-quality graphene layers at large scale [1]. The present study is focused on the optimization of hydrogen etching and growth of EG on the (0001) surfaces of the other commonly available polytype 4H-SiC. Etching in hydrogen as well as sublimation growth is carried out in a hot-wall reactor [2]. The dependence of the etching behavior on the hydrogen flow rate and annealing temperature was studied in the range of 0.2-3.0 slm and 1350-1500 ^∘C, respectively. Furthermore, the influence of process temperature and annealing time on the graphene growth was investigated. Surface composition and graphene thickness were obtained from XPS. The surface morphology after hydrogen etching and graphene growth was investigated by AFM. The onset of graphitization is witnessed by the formation of the (6√3×6√3)R30^∘ reconstruction at 1450 ^∘C for an annealing time of 15 min. The best result of monolayer graphene growth was achieved with an annealing time of 15 min at a temperature of 1700 ^∘C. In addition, bilayer graphene growth at step edges of the terraced SiC substrate was observed at 15 and 30 min annealing time. The substrate steps are mostly ordered and of similar height.

[1] K. V. Emtsev et al., Nature Mater. 8, 203 (2009).

[2] M. Ostler et al., Phys. Status Solidi B 247, 2924 (2010).