Project Details
Projekt
Proximity doping effects in epitaxial graphene: substrate, growth and post-growth treatment
Applicants
Dr. Rainer Stosch; Dr. Teresa Tschirner
Subject Area
Experimental Condensed Matter Physics
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 449119662
The carrier density and thus the position of the Fermi level in epitaxial graphene on SiC is critical for the various device applications. Hence, achieving a well-defined and highly homogeneous carrier density is essential for electrical quantum metrology, particularly for realizing quantum Hall standards in low magnetic fields. By growing homogenous large-area monolayer graphene with ultra-low terrace steps by polymer-assisted sublimation growth (PASG) and a post-growth molecular doping technique, we are able to achieve a highly homogeneous n- and p-type carrier density, allowing full quantization in the lowest possible fields. The exceptional doping uniformity near the Dirac point enables device operation in low-field conditions and the understanding of the different transport behaviors of n- and p-type graphene. In a second approach we focus on the investigation of electronic effects in intercalated graphene. By applying a new method to obtain lithographical control of the liquid metal intercalation technique (LiMIT) the graphene lattice is preserved while allowing precise control over doping and electronic modifications. Suitable device geometries are designed for systematic investigations of intercalation-induced electronic effects, particularly for quantum Hall effect studies and superconductivity. The presence, nature, and distribution of lattice defects are crucial for the efficiency and reproducibility of intercalation. Therefore, we aim to investigate the relationship between defect formation and metal diffusion dynamics, using both experimental techniques and theoretical modeling, to develop reproducible and site-selective intercalation strategies for advanced material design. With both approaches, refined n-and p-type doping and controlled liquid metal intercalation, devices will be designed that exploit the enhanced graphene properties and demonstrate their optimized quantum behavior properties e.g. quantum Hall effect (QHE), spin Hall effect (SHE), quantum anomalous Hall effect (QAHE), superconductivity, Klein-tunneling in p-n junctions etc. through low- temperature transport experiments.
DFG Programme
Research Units
International Connection
Netherlands, Sweden
Cooperation Partners
Professor Dr. Alexei Zakharov; Professor Dr. Ulrich Zeitler
