Duan Xinlei, Wang Tianyu, Fu Zhiwei, Liu Linhua, Yang Jia-Yue
School of Energy and Power Engineering, Shandong University, Jinan, Shandong 250061, China.
Optics & Thermal Radiation Research Center, Institute of Frontier and Interdisciplinary, Shandong University, Qingdao, 266237, China.
Phys Chem Chem Phys. 2023 Apr 5;25(14):10175-10183. doi: 10.1039/d3cp00036b.
The exfoliated two-dimensional (2D) GaO 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 GaO 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) GaO 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 GaO, accompanied by a large 'ion-clamped' dielectric constant Δ. The value of Δ is 3.77 and 4.60 for ML and BL GaO, respectively, indicating a large change in polarization in the external field. The electron mobility of 2D GaO enhances with increasing thickness despite the enhanced electron-phonon coupling strength and Fröhlich coupling constant. The predicted electron mobility for BL and ML GaO at a carrier concentration of 1.0 × 10 cm is 125.77 cm V s and 68.30 cm V s at room temperature, respectively. This work aims to unravel the scattering mechanisms beneath engineering electron mobility of 2D GaO for promising applications in high-power devices.
剥落的二维（2D）氧化镓开辟了新途径，可通过其提高的表面积与体积比和量子限制来微调载流子和热传输特性，从而改善基于氧化镓的功率电子器件的电热性能。然而，二维氧化镓中的载流子传输尚未得到充分研究，特别是考虑到它们较大的弗罗利希耦合常数。在此，我们主要通过添加极性光学声子（POP）散射，从第一性原理研究单层（ML）和双层（BL）氧化镓的电子迁移率。结果表明，POP散射是限制二维氧化镓电子迁移率的主要因素，同时伴随着较大的“离子钳制”介电常数Δ。对于ML和BL氧化镓，Δ的值分别为3.77和4.60，表明在外场中极化有很大变化。尽管电子 - 声子耦合强度和弗罗利希耦合常数增强，但二维氧化镓的电子迁移率随厚度增加而提高。在室温下，载流子浓度为1.0×10 cm时，预测的BL和ML氧化镓的电子迁移率分别为125.77 cm²V⁻¹s⁻¹和68.30 cm²V⁻¹s⁻¹。这项工作旨在揭示二维氧化镓工程电子迁移率背后的散射机制，以用于高功率器件中的有前景应用。
