Unraveling optical degradation mechanism of beta-Ga2O3 by Si4+ irradiation: A combined experimental and first-principles study

Wide bandgap beta-Ga2O3 is an ideal candidate material with broad application prospects for power electronic components in the future. Aiming at the application requirements of beta-Ga2O3 in space photoelectric devices, this work studies the influence of 40MeV Si ion irradiation on the microstructure and optical properties of beta-Ga2O3 epi-wafers. Raman spectroscopy analysis confirms that Si ion irradiation destroys the symmetric stretching mode of tetrahedral-octahedral chains in beta-Ga2O3 epi-wafers, and the obtained experimental evidence of irradiation leads to the enhanced defect density of V-O and V-Ga-V-O from x-ray photoelectron spectroscopy. Combined with first-principles calculations, we conclude that most configurations of V-O and V-Ga-V-O are likely non-radiative, leading to quenching of experimental photoluminescence intensity. Unraveling optical degradation mechanism and predicting the optical application of beta-Ga2O3 devices in the space environment by combining ground irradiation experiments with first-principles calculations still be one of the focuses of research in the future.