Why Two-Dimensional Semiconductors Generally Have Low Electron Mobility

Atomically thin (two-dimensional, 2D) semiconductors have shown great potential as the fundamental building blocks for next-generation electronics. However, all 2D that been experimentally made so far room-temperature electron mobility lower than of bulk silicon, which is not understood. Here, by using first-principles calculations and reformulating transport equations to isolate quantify contributions different mobility-determining factors, we show universally low originates from high density scatterings, intrinsic material with a parabolic band. The scatterings characterizes phonons can interact electrons be fully determined phonon band structures without knowledge electron-phonon coupling strength. Our work reveals underlying physics limiting offers descriptor quickly assess mobility.