How do the oxygen vacancies affect the photoexcited carriers dynamics in β-Ga2O3？

β-Ga2O3 is a rising star material for solar-blind photoelectronic detectors (PDs) since its excellent properties and lower cost than GaN and SiC. However, the high density of O vacancy (VO) strongly affect the performance of devices. In this work, we investigate the effect of VOs on carrier dynamics in β-Ga2O3 and its meaningful application in solar-blind PDs by the time-dependent density functional theory (TDDFT) and nonadiabatic molecular dynamics (NAMD). We find the three inequivalent VOs (VO1, VO2, and VO3) play different roles in carrier dynamics although they all introduce deep defect states in the bandgap, which significantly shorten the lifetime (τ) of carriers. VO1 and VO3 form nonradiative recombination centers, considerably decreasing the τ from 23.10 ns to 0.12 ns and 0.11 ns, respectively. VO2 forms shallow-level defects, and the τ is 0.47 ns, which weakens the decline of the carrier compared to VO1 and VO3. Our findings provide a different angle to understand the disputation on relationship between point defects and device performance based on β-Ga2O3, and to further improve the device performance by defect engineering.