title: Structure, properties, and dynamics of oxygen vacancies in amorphous SiO2.
abstract: Oxygen vacancies in SiO2 have long been regarded as bistable, forming a Si-Si dimer when neutral and a puckered configuration when positively charged. We report first-principles calculations of O vacancies in amorphous SiO2 supercells that unveil significantly more complex behavior. We find that the vast majority of O vacancies do not pucker after capture of a hole, but are shallow traps. The remaining vacancies exhibit two distinct types of puckering. Upon capturing an electron, one type forms a metastable dipole, while the other collapses to a dimer. A statistical distribution of O vacancies is obtained, and the implications for charge transport and trapping in SiO2 are discussed.
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA.
authors.forename: Zhong-Yi
authors.initials: ZY
authors.lastname: Lu
authors.forename: C J
authors.initials: CJ
authors.lastname: Nicklaw
authors.forename: D M
authors.initials: DM
authors.lastname: Fleetwood
authors.forename: R D
authors.initials: RD
authors.lastname: Schrimpf
authors.forename: S T
authors.initials: ST
authors.lastname: Pantelides