"Metal-insulator crossover in monolayer MoS2" by I. Castillo, T. Sohier et al.
 

Metal-insulator crossover in monolayer MoS2

Document Type

Article

Publication Date

8-13-2023

Abstract

We report on transport measurements in monolayer MoS2 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 cm2 V−1 s−1 is among the largest obtained in CVD-grown MoS2 monolayer devices. These measurements show that electronic transport is of the insulating type for σ ≤ 1.4e 2/h and n ≤ 1.7 × 1012 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.

Identifier

85160965021 (Scopus)

Publication Title

Nanotechnology

External Full Text Location

https://doi.org/10.1088/1361-6528/acd3f7

e-ISSN

13616528

ISSN

09574484

PubMed ID

37164000

Issue

33

Volume

34

Grant

ANR-18-CE24-0004

Fund Ref

Australian Research Council

This document is currently not available here.

Share

COinS