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

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 [Formula: see text] (zigzag direction) and [Formula: see text] [Formula: see text] (Armchair direction), respectively. The deformation potential theory (DPT) based on longitudinal acoustic 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 including Fröhlich interaction is reduced to [Formula: see text] and [Formula: see text] [Formula: see text]. Therefore, the electron mobility for InSe is controlled by the scattering from polar phonons. The mobility can be increased to [Formula: see text] and [Formula: see text] [Formula: see text] under 4% biaxial strain. This result is compared with the experiment, and some disagreements are explained.