Multiphonon mechanism of the ionization of traps in Al2O3: Experiment and numerical simulation

Charge transfer in Al2O3 has been investigated experimentally and theoretically. The experimental results are in qualitative agreement with the theory of the multiphonon ionization of deep centers. The thermal (W T = 1.5 eV) and optical (W opt = 3.0 eV) energies of the deep centers have been determined. It has been found that the experimental data are unsatisfactorily described by the Pool-Frenkel mechanism, which provides a non-physically small frequency factor and anomalously large effective tunneling mass.