Defects responsible for charge carrier removal and correlation with deep level introduction in irradiated beta-Ga2O3

Abstract

Carrier removal rates and electron and hole trap densities in beta-Ga2O3 films grown by hydride vapor phase epitaxy (HVPE) and irradiated with 18MeV alpha-particles and 20MeV protons were measured and compared to the results of modeling. The electron removal rates for proton and alpha-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 E-c - (0.75-0.78) eV, E3 at E-c - (0.95-1.05) eV, and E4 at E-c - 1.2 eV. The introduction rates of these traps are similar for the 18MeV alpha-particles and 20MeV protons and are much lower than the carrier removal rates. Published by AIP Publishing.