Nontrivial role of polar optical phonons in limiting electron mobility of two-dimensional Ga2O3 from first-principles

Xinlei Duan; Tianyu Wang; Zhiwei Fu; Linhua Liu; Jia-Yue Yang

doi:10.1039/d3cp00036b

Nontrivial role of polar optical phonons in limiting electron mobility of two-dimensional Ga₂O₃ from first-principles

Phys Chem Chem Phys. 2023 Apr 5;25(14):10175-10183. doi: 10.1039/d3cp00036b.

Authors

Xinlei Duan^{1

2}, Tianyu Wang³, Zhiwei Fu^{1

4}, Linhua Liu^{1

2}, Jia-Yue Yang^{1

2}

Affiliations

¹ School of Energy and Power Engineering, Shandong University, Jinan, Shandong 250061, China. liulinhua@sdu.edu.cn.
² Optics & Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary, Shandong University, Qingdao, 266237, China.
³ School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁴ Science and Technology on Reliability Physics and Application of Electronic Component Laboratory, China Electronic Product Reliability and Environmental Testing Research Institute, Guangzhou 510610, China.

PMID: 36976635
DOI: 10.1039/d3cp00036b

Abstract

The exfoliated two-dimensional (2D) Ga₂O₃ opens new avenues to fine-tune the carrier and thermal transport properties for improving the electro-thermal performance of gallium oxide-based power electronics with their enhanced surface-to-volume ratios and quantum confinement. Yet, the carrier transport in 2D Ga₂O₃ has not been fully explored, especially considering their large Fröhlich coupling constants. Herein, we mainly investigate the electron mobility of monolayer (ML) and bilayer (BL) Ga₂O₃ from first-principles by adding polar optical phonon (POP) scattering. The results show that POP scattering is the dominant factor limiting the electron mobility for 2D Ga₂O₃, accompanied by a large 'ion-clamped' dielectric constant Δε. The value of Δε is 3.77 and 4.60 for ML and BL Ga₂O₃, respectively, indicating a large change in polarization in the external field. The electron mobility of 2D Ga₂O₃ enhances with increasing thickness despite the enhanced electron-phonon coupling strength and Fröhlich coupling constant. The predicted electron mobility for BL and ML Ga₂O₃ at a carrier concentration of 1.0 × 10¹² cm^-2 is 125.77 cm² V^-1 s^-1 and 68.30 cm² V^-1 s^-1 at room temperature, respectively. This work aims to unravel the scattering mechanisms beneath engineering electron mobility of 2D Ga₂O₃ for promising applications in high-power devices.