| AVS 63rd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D+MI-ThM |
| Session: | Properties of 2D Materials including Electronic, Magnetic, Optical, Mechanical, Thermal Properties |
| Presenter: | Ludwig Bartels, University of California - Riverside |
| Authors: | M. Gomez, University of California - Riverside J. Martinez, University of California - Riverside M. Valentin, University of California - Riverside E. Preciado, University of California - Riverside V. Klee, University of California - Riverside C. Merida, University of California - Riverside L. Bartels, University of California - Riverside |
| Correspondent: | Click to Email |
We utilize a combination of X-ray photoelectron spectroscopy, transport measurements and optical as well as acoustic excitation to study the impact of the formation of metal contacts to transition metal dichalcogenide films on the electronic structure of the films. Photoelectron spectroscopy permits us to follow the formation of a Schottky-like barriers with increasing metal film thickness on the Angstrom scale. We utilize core level spectroscopy to indicate the evolution of the MoS2 valence band during metal deposition. Our findings indicate that single layer MoS2 films adopt the character of the metal (Fermi-level pinning) resulting in a Fermi-level position in the MoS2 semiconducting gap that is – depending on the metal work function –indicative of a p-type semiconductor, even though the native carriers in an MoS2 film are electrons. As a consequence, metal-TMD-metal junctions may best be understood as p-n-p junctions. Numerous ancillary measurements support this hypothesis.