Theoretical study of carrier transport in supported and gated two-dimensional transition metal dichalcogenides

Abstract

We investigate theoretically the impact of the dielectric environment on electronic transport in transition metal dichalcogenide monolayers. The low-field carrier mobility in free-standing layers is calculated using well-known ab initio methods, and the study is extended to layers in double-gate structures using the dielectric continuum approximation. In particular, we account for the screening of the electron–phonon interaction by the free carriers in the layer and by the dielectric environment. In addition, we include scattering with the hybrid interface optical-phonon/plasmon excitations (“remote phonons”). We find that whereas the presence of insulators with a high dielectric constant may increase the carrier mobility when ignoring the latter process, scattering with the hybrid interface excitations negates this beneficial effects and depresses the mobility significantly below its value in free-standing monolayers.