Metal-insulator transition in monolayer MoS${}_2$ via contactless chemical doping

Abstract

Much effort has been made to modify the properties of transition metal dichalcogenide layers via their environment as a route to new functionalization. However, it remains a challenge to induce large electronic changes without chemically altering the layer or compromising its two-dimensionality. Here, a non-invasive technique is used to shift the chemical potential of monolayer MoS${}_2$ through p- and n-type doping of graphene (Gr), which remains a well-decoupled 2D substrate. With the intercalation of oxygen (O) under Gr, a nearly rigid Fermi level shift of 0.45 eV in MoS${}_2$ is demonstrated, whereas the intercalation of europium (Eu) induces a metal-insulator transition in MoS${}_2$, accompanied by a giant band gap reduction of 0.67 eV. Additionally, the effect of the substrate charge on 1D states within MoS${}_2$ mirror-twin boundaries (MTBs) is explored. It is found that the 1D nature of the MTB states is not compromised, even when MoS${}_2$ is made metallic. Furthermore, with the periodicity of the 1D states dependent on substrate-induced charging and depletion, the boundaries serve as chemical potential sensors functional up to room temperature.

References in corpus (14)

• Doping graphene with metal contacts
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• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
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• Tomonaga-Luttinger liquid in a box: electrons confined within MoS${}_2$ mirror twin boundaries
• Gated Tuned Superconductivity and Phonon Softening in Mono- and Bilayer MoS${}_2$
• Band Bending and Valence Band Quantization at Line Defects in MoS${}_2$
• Comprehensive tunneling spectroscopy of quasi-freestanding MoS${}_2$ on graphene on Ir(111)
• Manipulating Hubbard-type Coulomb blockade effect of metallic wires embedded in an insulator

Cited by in corpus (5)

• Unconventional charge-density-wave gap in monolayer NbS${}_2$
• Modulated Kondo screening along magnetic mirror twin boundaries in monolayer MoS2 on graphene
• Novel 2D vanadium sulphides: synthesis, atomic structure engineering and charge density waves
• Which chromium-sulfur compounds exist as 2D material?
• Visualizing intercalation effects in 2D materials using AFM based techniques