First principles study of oxygen-deficient centers in pure and Ge-doped silica

Abstract : Using ab initio calculations on 108 atoms pure- and Ge-doped (2.8 mol%) silica-based supercells, we performed a statistical study on the electronic structure and energetic contribution of neutral oxygen vacancies, also named Oxygen Deficient Centers (ODCs). All the 72 oxygen sites in the amorphous silica (a-SiO2) cell were considered as possible candidates for the formation of the vacancies leading to study 72 different Si-ODCs ('Si\Si' bond) and 144 Ge-ODCs ('Ge\Si' bond). The distributions of structural parameters and formation energies of the ODCs were evaluated through Density Functional Theory calculations. The obtained parameters showed a wide distribution that can be mainly associated with the differences in the local environments surrounding the point defects. Weshow that the formation energies of Si and Ge-ODCs generated from the same oxygen site of our supercell are correlated. Moreover, the local asymmetry around the Si\Ge or Ge\Si bond can also affect their formation energies, providing a strong evidence for the influence of short-range environment on the ODC generation efficiency.
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Submitted on : Wednesday, April 20, 2011 - 2:32:11 PM
Last modification on : Tuesday, August 6, 2019 - 9:02:30 AM

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N. Richard, Sébastien Girard, L. Martin-Samos, V. Cuny, A. Boukenter, et al.. First principles study of oxygen-deficient centers in pure and Ge-doped silica. Journal of Non-Crystalline Solids, Elsevier, 2011, 357, pp.1994-1999. ⟨10.1016/j.jnoncrysol.2010.12.069⟩. ⟨ujm-00587457⟩

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