Over One Order of Magnitude Enhancement in Hole Mobility of 2D III-V Semiconductors through Valence Band Edge Shift

Abstract

Two-dimensional (2D) semiconductors show great potential to sustain Moore's law in the era of ultra-scaled electronics. However, their scalable applications are severely constrained by low hole mobility. In this work, we take 2D-GaAs as a prototype of III-V semiconductors to investigate the effects of quantum anharmonicity (QA) on hole transport, employing the stochastic self-consistent harmonic approximation assisted by the machine learning potential. It is found that the room-temperature hole mobility of 2D-GaAs is reduced by $\sim$44% as the QA effects are incorporated, which is attributed to the enhanced electron-phonon scattering from the out-of-plane acoustic polarization. The valence band edge shift (VBES) strategy is proposed to increase the hole mobility by $\sim$1600% at room temperature, which can be realized by 1% biaxial compressive strain. The electron-phonon scattering rate is dramatically decreased due to the full filtering of the original interband electron-phonon scattering channels that existed in the flat hole pocket. The VBES strategy can be further extended to other 2D III-V semiconductors to promote their hole mobilities.