Impact of radiation and electron trapping on minority carrier transport in p -Ga₂O₃

Highly resistive undoped p-type gallium oxide samples were subjected to cumulative proton irradiation with energies ranging from 25 to 70 keV and doses in the 1.6 × 1014-3.6 × 1014 cm-2 range. Proton irradiation resulted in up to a factor of 2 reduction of minority electron diffusion length in the samples for temperatures between ∼300 and 400 K. Electron injection into the samples under test using a scanning electron microscope beam leads to pronounced elongation of diffusion length beyond the pre-irradiation values, thus demonstrating stable (days after injection) recovery of adverse radiation impact on minority carrier transport. The activation energy of 91 meV estimated from the temperature dependent diffusion length vs electron injection duration experiments is likely related to the local potential barrier height for native defects associated with the phenomenon of interest.