Machine learning-assisted investigation on the thermal transport of β-Ga2O3 with vacancy

SL Dong and GW Zhang and GZ Zhang and X Lan and XY Wang and GM Xin, JOURNAL OF CHEMICAL PHYSICS, 161, 214705 (2024).

DOI: 10.1063/5.0237656

beta-Ga2O3 is a promising ultra-wide bandgap semiconductor in high-power and high-frequency electronics. The low thermal conductivity of beta- Ga2O3, which can be further suppressed by the intrinsic vacancy, has been a major bottleneck for improving the performance of beta-Ga2O3 power devices. However, deep knowledge on the thermal transport mechanism of beta-Ga2O3 with defect is still lacking now. In this work, the thermal transport of beta-Ga2O3 with vacancy defects is investigated using the machine learning-assisted calculation method. First, the machine learning moment tensor potential (MTP), which can accurately describe the lattice dynamics behaviors of pristine beta-Ga2O3 and solves the problem of low computational efficiency of existing computational models in beta-Ga2O3 large-scale simulations, is developed for studying the thermal transport of the pristine beta-Ga2O3. Then, the MTP is further developed for investigating the thermal transport of beta-Ga2O3 with vacancy and the thermal conductivity of beta-Ga2O3 with oxygen atom vacancies, which are evaluated by machine learning potential combined with molecular dynamics. The result shows that 0.52% oxygen atom vacancies can cause a 52.5% reduction in the thermal conductivity of beta-Ga2O3 100 direction, illustrating that thermal conductivity can be observably suppressed by vacancy. Finally, by analyzing the phonon group velocity, participation ratio, and spectral energy density, the oxygen atom vacancies in beta-Ga2O3 are demonstrated to lead to a significant change in harmonic and anharmonic phonon activities. The findings of this study offer crucial insights into the thermal transport properties of beta-Ga2O3 and are anticipated to contribute valuable knowledge to the thermal management of power devices based on beta- Ga2O3.

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