Advancing intrinsic carrier mobility estimation in transition metal trichalcogenide monolayers using DFT-BTE

Abstract

The Boltzmann transport equation (BTE) based intrinsic carrier mobility estimation significantly improves accuracy, which is crucial for assessing the performances of the materials within the devices. Herein, we explore the highly anisotropic, semiconducting 2D transition metal trichalcogenide monolayers (TMTC) MX3 (M = Ti, Zr, Hf and X = S, Se) for their transport properties. Remarkably, the electron carrier mobility obtained by combining BTE with density functional theory (DFT) in TiS3 monolayer has reached ∼1400 cm2/V.s. This finding stands in stark contrast to the electron mobility of ∼104 cm2/V·s obtained using a formalism built on the effective mass approximation. The marked disparity in mobility estimation underscores the crucial role played by the BTE in elevating precision. Alongside, a pronounced anisotropy in carrier mobility has been observed in these monolayers, particularly concerning lattice directions and electron-to-hole carrier mobility. Overall, this study seeks to fill out the voids and focuses on accurate estimation of high carrier mobility in TMTC monolayers using DFT-BTE.