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arXiv · 2112.04978

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

Camiel van Efferen·Clifford Murray·Jeison Fischer·Carsten Busse·Hannu-Pekka Komsa·Thomas Michely·Wouter Jolie
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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.

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Camiel van Efferen, Clifford Murray, Jeison Fischer, Carsten Busse, Hannu-Pekka Komsa, Thomas Michely, Wouter Jolie. 2021-12-09. Metal-insulator transition in monolayer MoS$_2$ via contactless chemical doping. https://doi.org/10.1088/2053-1583%2Fac5d0f

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