【International Papers】Electron beam irradiation-induced transport and recombination in p-type gallium oxide grown on (001) β-Ga₂O₃ substrate

      Researchers from the University of Central Florida have published a dissertation titled "Electron beam irradiation-induced transport and recombination in p-type gallium oxide grown on (001) β-Ga₂O₃ substrate" in Journal of Applied Physics.

Abstract

      This study investigates minority electron diffusion length and carrier recombination phenomena in p-type 300 nm-thick Ga₂O₃ films homoepitaxially grown over a (001) tin-doped β-Ga₂O₃ conductive substrate. This research is novel due to its systematic and near-simultaneous measurements in the top layer of a p-Ga₂O₃/n-Ga₂O₃ structure using independent electron beam-induced current and cathodoluminescence techniques. Previous work primarily focused on heteroepitaxial architectures or gallium oxide grown over insulating substrates of the same material. In this work, the activation energies related to point defects in gallium oxide were extracted from temperature-dependent incremental electron beam irradiation experiments to gain insight into the defect landscape and its influence on minority carrier transport and recombination dynamics.

Conclusion

      This investigation employed Electron Beam-Induced Current (EBIC) to characterize the minority electron diffusion length in undoped, homoepitaxial p-type gallium oxide grown on a conductive (001) Sn-doped substrate. Measurements were carried out across a temperature range of 25–120 °C and under electron irradiation durations totaling up to 1200 s. This revealed two trends: a continuous decrease in L with increasing temperature and a near-linear increase in L under prolonged irradiation duration. Both observed trends are consistent with the previously published results for p-type Ga₂O₃. The activation energy ΔE_A,I = 68 meV, obtained in this work, is comparable to that for p-Ga₂O₃ homoepitaxially grown on (010) Fe-doped substrates (72 meV). Based on the determined ΔE_A,I, the gallium vacancy-related acceptor concentration, N_A, was calculated as 1.15 × 10¹⁸ cm⁻³.