Model of a switching oxide trap in amorphous silicon dioxide

We present a model of a switching oxide trap in amorphous silicon dioxide on the basis of quantum chemical calculations on clusters of atoms. We show that the positively-charged defect center proposed in previous papers [Uchino et al., Phys. Rev. B 62, 2983 (2000); Phys. Rev. Lett. 86, 5522 (2001)] can capture an electron without accompanying complex atomic rearrangements, forming a metastable hole-electron pair that can in turn emit an electron. The present model also gives a reasonable account for the cathodoluminescence and thermally stimulated luminescence emissions at 445 nm from amorphous silicon dioxide.