Theoretical prediction of intrinsic electron mobility of monolayer InSe: first-principles calculation

Abstract

Recently, a novel two-dimensional (2D) semiconductor, InSe, has attracted great attention due to its potential applications in optoelectronic devices and field effect transistors. In this study, phonon-limited mobility is investigated by the first-principles calculation. At 300 K, the intrinsic electron mobilities calculated from the electron-phonon coupling (EPC) matrix element are as high as µx=9.85×102(Zigzag direction) and µy=1.06×103cm2V−1s−1(Armchair direction), respectively. The deformation potential theory (DPT) based on longitudinal acoustic phonon and optical phonon scattering is also employed to investigate electron mobility. The mobility from optical phonon scattering is much higher than that from longitudinal acoustic phonon scattering. If the polarization characteristics of InSe are not considered, the electron mobility calculated from EPC matrix element is closed to that from the longitudinal acoustic phonon DPT. In this study, we have also investigated the effect of polarization properties in 2D InSe on electron mobility. At 300 K, the electron mobility for considering Fröhlich interaction is reduced to µx=2.96×102cm2V−1s−1 and µy=3.34×102cm2V−1s−1. Therefore, the electron mobility for InSe is controlled by the scattering from polar phonons. The mobility can be increased to µx=3.46×102and µy=3.78×102cm2V−1s−1under 4 % biaxial strain. This result is compared with the experiment, and some disagreements are explained.