Giant modulation of the electron mobility in semiconductor Bi$_2$O$_2$Se via incipient ferroelectric phase transition

TL;DR

This study reveals that an incipient ferroelectric transition in Bi$_2$O$_2$Se significantly enhances electron mobility, offering a new approach for high-performance layered semiconductor design through phase and dielectric engineering.

Contribution

It demonstrates that ferroelectric phase transition in Bi$_2$O$_2$Se can be exploited to achieve ultrahigh electron mobility, a novel mechanism for mobility enhancement.

Findings

Electron mobility can reach 10$^4$ to 10$^6$ cm$^2$V$^{-1}$s$^{-1}$ across doping levels.

A small elastic strain induces ferroelectric transition, boosting dielectric permittivity.

Mobility increases by over an order of magnitude near the ferroelectric transition.

Abstract

High-mobility layered semiconductors have the potential to enable the next-generation electronics and computing. This paper demonstrates that the ultrahigh electron mobility observed in the layered semiconductor Bi$_2$O$_2$Se originates from an incipient ferroelectric transition that endows the material with a robust protection against mobility degradation by Coulomb scattering. Based on first-principles calculations of electron-phonon interaction and ionized impurity scattering, it is shown that the electron mobility of Bi$_2$O$_2$Se can reach 10$^4$ to 10$^6$ cm$^2$V$^{-1}$s$^{-1}$ over a wide range of realistic doping concentrations. Furthermore, a small elastic strain of 1.7% can drive the material toward a unique interlayer ferroelectric transition, resulting in a large increase in the dielectric permittivity and a giant enhancement of the low-temperature electron mobility by more than an order of magnitude. These results establish a new route to realize high-mobility layered semiconductors via phase and dielectric engineering.