Metal-insulator crossover in monolayer MoS 2 .

Autor: Castillo I; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France., Sohier T; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.; Nanomat/QMAT/CESAM, University of Liège, Belgium., Paillet M; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France., Cakiroglu D; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.; Engineered Nanosystems Group, Department of Neuroscience and Biomedical Engineering, School of Science, Aalto University, Aalto, Finland., Consejo C; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France., Wen C; Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia PA 19104, United States of America., Wasem Klein F; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France., Zhao MQ; Otto H. York Department of Chemical and Materials Engineering, New Jersey Institute of Technology, Newark, New Jersey, NJ 07103, United States of America.; Department of Physics and Astronomy, University of Pennsylvania, Philadelphia PA 19104, United States of America., Ouerghi A; Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay, France., Contreras S; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France., Johnson ATC; Department of Physics and Astronomy, University of Pennsylvania, Philadelphia PA 19104, United States of America., Verstraete MJ; Nanomat/QMAT/CESAM, University of Liège, Belgium., Jouault B; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France., Nanot S; Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, France.
Jazyk: angličtina
Zdroj: Nanotechnology [Nanotechnology] 2023 Jun 01; Vol. 34 (33). Date of Electronic Publication: 2023 Jun 01.
DOI: 10.1088/1361-6528/acd3f7
Abstrakt: We report on transport measurements in monolayer MoS 2 devices, close to the bottom of the conduction band edge. These devices were annealed in situ before electrical measurements. This allows us to obtain good ohmic contacts at low temperatures, and to measure precisely the conductivity and mobility via four-probe measurements. The measured effective mobility up to μ eff = 180 cm 2 V -1 s -1 is among the largest obtained in CVD-grown MoS 2 monolayer devices. These measurements show that electronic transport is of the insulating type for σ ≤ 1.4 e 2 / h and n ≤ 1.7 × 10 12 cm -2 , and a crossover to a metallic regime is observed above those values. In the insulating regime, thermally activated transport dominates at high temperature ( T > 120 K). At lower temperatures, conductivity is driven by Efros-Schklovkii variable range hopping in all measured devices, with a universal and constant hopping prefactor, that is a clear indication that hopping is not phonon-mediated. At higher carrier density, and high temperature, the conductivity is well modeled by the Boltzmann equation for a non-interacting Fermi gas, taking into account both phonon and impurity scatterings. Finally, even if this apparent metal-insulator transition can be explained by phonon-related phenomena at high temperature, the possibility of a genuine 2D MIT cannot be ruled out, as we can observe a clear power-law diverging localization length close to the transition, and a one-parameter scaling can be realized.
(© 2023 IOP Publishing Ltd.)
Databáze: MEDLINE
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