Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 30: Focus Session: Young Semiconductor Forum

HL 30.1: Invited Talk

Wednesday, March 19, 2025, 09:30–10:00, H13

Exploring semiconducting epigraphene grown by polymer-assisted sublimation growth — •Teresa Tschirner, Julia Guse, Stefan Wundrack, Frank Hohls, Klaus Pierz, and Hans Werner Schumacher — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

Epitaxial graphene on SiC is a potential candidate in a variety of applications, such as the fabrication of 2D heterostructures and the intercalation of graphene layers with other materials for engineering new electronic material systems. Important for the quality of the graphene is the 0th layer, or buffer layer, which is covalently bonded to the SiC substrate. The buffer layer itself can be functionalized by intercalation. In a recent study it was shown that an electronic bandgap can be opened in the otherwise gapless buffer layer. The semiconducting epigraphene (SEG) on SiC has a bandgap of 0.6 eV and high room temperature mobilities (5000 cm²/Vs), much larger than silicon and other 2D-semiconductors [1]. In this study we grow high-quality buffer layers not only across single terraces as in the aforementioned study but on millimeter scale, due to an advanced growth technique preventing step bunching and large terrace step heights. We use a polymer-assisted sublimation growth (PASG) method, where pretreatment of the SiC substrate supplies additional carbon and stabilizes the SiC surface by rapid buffer layer-formation preventing step-bunching. We investigate the growth parameters for homogeneous buffer layer formation with our PASG method and systematically study its structural properties and characteristics. [1] J. Zhao et al., Nature 625, 60 (2024).

Keywords: graphene; epitaxy; buffer layer; semiconducting epigraphene