Thermal transport of defective β-Ga2O3 and B(In)GaO3 alloys from atomistic simulations

Abstract

β-Ga2O3 is a new generation of semiconductor material with a wide bandgap of 4.9 eV. However, the β-Ga2O3 devices inevitably produce defects within them after irradiation, leading to changes in their thermal conductivities. At present, the effect of radiation-damage-induced defects on thermal conductivity of β-Ga2O3 has not been carried out. Herein, we have employed molecular dynamics simulations to investigate the impact of defects on the thermal transport of β-Ga2O3, and the obtained thermal conductivity of non-defect β-Ga2O3 is in good agreement with recent reports. Our findings indicate that the thermal conductivity of β-Ga2O3 at room temperature exhibits a consistent decrease with an increase in the concentration of Ga vacancies, but shows a decreasing and then increasing trend as the number of O vacancies increases. In addition, doping/alloying is found to improve the irradiation resistance of β-Ga2O3 based on reported defect formation energy calculations, so the mechanism of alloying effect on the thermal conductivity is deeply analyzed through first-principles calculations. Moreover, the lattice thermal conductivities of ordered InGaO3 and BGaO3 alloys are predicted by solving the phonon Boltzmann transport equation. The obtained results that κ(Ga2O3) = κ(BGaO3) > κ(InGaO3) are attributed to the combined effect of volume, specific heat capacity, group velocity, and phonon lifetime of the three materials. This work can help to disclose the radiation damage influence on thermal properties of β-Ga2O3 semiconductors.