Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 56: 2D Materials beyond Graphene
O 56.5: Poster
Dienstag, 21. März 2017, 18:30–20:30, P2-EG
Low Temperature Scanning Tunneling Spectroscopy on MoS2 nanoflakes on Au(111) — •Daniela Dombrowski1,2 and Carsten Busse1,2 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Materialphysik, Westfälische Wilhelms-Universität Münster
We perform low temperature scanning tunneling spectroscopy at 5 K of MoS2 nanoflakes grown on Au(111) by a combination of physical and chemical vapour deposition. We find a band gap of approx. 1.9 eV and pronounced peaks, originating from the MoS2 bands. The Shockley-surface state at 0.5 eV is present on the bare gold surface, but absent below the MoS2 islands.
Furthermore, we take advantage of the spatial resolution of scanning tunneling spectroscopy to measure the influence of the moiré superstructure arising from the lattice mismatch between the MoS2 layer and the underlying gold substrate. We observe a significant shift of the valence band edge, whereas the conduction band remains almost unchanged, hence leading to a variation of the gap energy induced by the moiré pattern.
Finally, we find a new state right above the valence band, which is associated with the edge of the MoS2 flakes.