The ability of intrinsic defects in SiO2 to capture electrons and holes was investigated by quantum-chemical methods. It was established that a twofold-coordinated Si atom with two unpaired electrons, namely, the silylene center =Si:, and a Si–Si bond, namely, the O vacancy Si–Si, were electron–hole traps in SiO2. The properties of a defect in the form of an associate of the two above centers were studied. It was shown that this defect could capture electrons and holes; i.e., it was an amphoteric defect in SiO2. The optical absorption spectrum of the studied associate virtually coincides with that of the oxy radical (Si–O▪) in silicon dioxide.

Interaction with Charge Carriers and the Optical Absorption Spectrum of an Associate Formed by Elementary Defects (an Oxygen Vacancy and a Silylene Center) in SiO2. A.E.Patrakov, V.A.Gritsenko, G.M.Zhidomirov: Physics of the Solid State, 2004, 46[11], 2021-5