SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Poster Session V: 2D Materials: Electronic structure, excitations, etc. I
O 66.6: Poster
Mittwoch, 3. März 2021, 10:30–12:30, P
Metal-to-insulator transition in MoS2 by contactless chemical gating — •Wouter Jolie1,2, Clifford Murray1, Camiel van Efferen1, Jeison A. Fischer1, Carsten Busse2, Hannu-Pekka Komsa3, and Thomas Michely1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Germany — 3Microelectronics Research Unit, University of Oulu, Finland
We present an effective way to gate semiconducting transition metal dichalcogenides without changing their direct chemical environment. The principle is demonstrated for MoS2 on graphene on Ir(111). Intercalation of oxygen (europium) between graphene and Ir(111) removes (adds) charge in graphene, leading to a strong gating effect in MoS2. Using scanning tunneling microscopy, we show that removing charge with oxygen leads to a 450 meV shift of the MoS2 band gap with respect to the Fermi level. Adding charge with europium shifts the conduction band below the Fermi energy, accompanied by a band gap reduction of 700 meV due to renormalization. In addition, we find that gating also shifts the one-dimensional band present in MoS2 mirror twin boundaries, which can be used as gating sensors.