Defect-controlled carrier transport in amorphous SiO₂

Abstract

The defect-controlled transport properties of the photogenerated electrons in amorphous SiO₂, the low-temperature mobility of approximately 40 cm² V⁻¹ s⁻¹ and the lifetime of approximately l.4 × 10⁻⁸ s, are shown to be determined by interaction with neutral intimate-valence-alternation pairs, defects consisting of charged, and over- and under-coordinated oxygen atoms, C₃ ⁺ and C₁ ⁻ respectively. The holes move by small-polaron hopping, and a dispersive character in their transport may be associated with trapping at the same defects.