Carrier Mobility of Two-Dimensional Indium Selenide*

Owing to its exceptionally high electron mobility, indium selenide (InSe) is emerging as one of the most promising layered semiconductors for two-dimensional electronics and optoelectronics. However, the intrinsic carrier mobility of InSe in the monolayer limit and the corresponding carrier scattering mechanisms remain unknown. By performing ab initio calculations of the intrinsic carrier mobility of InSe in the Boltzmann transport formalism, we find that the electron carriers in InSe are predominantly scattered by the coupling to longitudinal-optical phonons, namely the Fröhlich interaction. We also find that the carrier mobility of InSe exhibits strong layer dependence. At 300 K, the electron mobilities of InSe are found to be 120, 220, and 1060 cm²V^-1s^-1 for monolayer, bilayer and bulk, respectively, in good agreement with transport measurements.