Deep electron and hole traps in 10 MeV proton irradiated high-quality b-Ga 2 O 3 films grown by Hydride Vapor Phase Epitaxy (HVPE) on bulk b-Ga 2 O 3 substrates were measured by deep level transient spectroscopy with electrical and optical injection, capacitance-voltage profiling in the dark and under monochromatic irradiation, and also electron beam induced current. Proton irradiation caused the diffusion length of charge carriers to decrease from 350-380 lm in unirradiated samples to 190 lm for a fluence of 10 14 cm À2 , and this was correlated with an increase in density of hole traps with optical ionization threshold energy near 2.3 eV. These defects most likely determine the recombination lifetime in HVPE b-Ga 2 O 3 epilayers. Electron traps at E c-0.75 eV and E c-1.2 eV present in as-grown samples increase in the concentration after irradiation and suggest that these centers involve native point defects.

Carrier removal rates and electron and hole trap densities in β-Ga2O3 films grown by hydride vapor phase epitaxy (HVPE) and irradiated with 18 MeV α-particles and 20 MeV protons were measured and compared to the results of modeling. The electron removal rates for proton and α-radiation were found to be close to the theoretical production rates of vacancies, whereas the concentrations of major electron and hole traps were much lower, suggesting that the main process responsible for carrier removal is the formation of neutral complexes between vacancies and shallow donors. There is a concurrent decrease in the diffusion length of nonequilibrium charge carriers after irradiation, which correlates with the increase in density of the main electron traps E2* at Ec − (0.75–0.78) eV, E3 at Ec − (0.95–1.05) eV, and E4 at Ec − 1.2 eV. The introduction rates of these traps are similar for the 18 MeV α-particles and 20 MeV protons and are much lower than the carrier removal rates.

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