Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Poster: 2D Materials

O 29.34: Poster

Dienstag, 19. März 2024, 12:30–14:30, Poster A

Imaging the local Electrochemical Potential of Graphene with Scanning Tunneling Potentiometry — Toni Marković, Wei Huang, •Mark Canavan, Jeong Ah Seo, Pietro Gambardella, and Sebastian Stepanow — Department of Materials, ETH Zurich, 8093 Zurich, Switzerland

Two-dimensional material systems and heterostructures have recently emerged as a promising class of materials for high performance electronic devices. In such systems, understanding the influence nanoscale transport effects, such as scattering at atomic defects and interfaces is crucial. Scanning Tunneling Potentiometry (STP) allows for studying charge transport on the nanoscale by relating the local electro-chemical potential to morphological features of the system. STP maintains the angstrom spatial sensitivity of conventional STM while imaging modifications to the ECP with uV resolution, offering a way to potentially investigate transport phenomena beyond the diffusive regime. Here, we present an implementation of STP in a commercial RHK Pan-Scan STM with an integrated flow cryostat capable of reaching temperatures of 12K [1]. We perform STP on epitaxial graphene to measure the sheet resistance of monolayer and bilayer grown on SiC as well resistances of interfaces between them. To investigate transport effects beyond the diffusive regime, using back-gated graphene samples would allow for STP measurements with charge carries at the Dirac point.

[1] T. Marković et al. Rev. Sci. Instrum. 92, 103707 (2021)

Keywords: Scanning Tunneling Microscopy; Scanning Tunneling Potentiometry; Epitaxial Graphene; Transport