Anharmonic phonon scattering study in wide bandgap semiconductor β -Ga2O3 by Raman spectroscopy

The low thermal conductivity of β-Ga2O3 single crystal imposes limitations on its device performance under high-temperature and high-power conditions. Phonons are widely recognized to play the main role in heat transport, while the anharmonic scattering among these quasi-particles significantly diminishes thermal conductivity. Therefore, investigating the anharmonic phonon scattering within β-Ga2O3 single crystal holds paramount significance. In this study, we mainly employed temperature-dependent Raman spectroscopy and first-principles calculation to give a quantitative analysis on the anharmonic phonon scattering. The mode Grüneisen parameters and temperature-dependent thermal expansion coefficient were studied. Strong anharmonic phonon scattering was also confirmed, which was mainly caused by cubic scattering, but quartic scattering is also nonnegligible and causes nonlinear linewidth broadening. Moreover, high wavenumber peaks are more likely to undergo asymmetric phonon scattering by comparing the symmetric and asymmetric scattering models. In all, this study provides a profound understanding of the anharmonic phonon scattering properties within the β-Ga2O3 single crystal. It enriches our understanding of quasi-particle interaction dynamics and offers theoretical pathways for expanding the applications of β-Ga2O3 single crystal and optimizing its device performance.