Oxygen defects in amorphous Al2O3
- Chaire de Simulation à l’Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
DOI10.24435/materialscloud:2019.0026/v1 (version v1, submitted on 30 May 2019)
How to cite this entry
Zhendong Guo, Francesco Ambrosio, Alfredo Pasquarello, Oxygen defects in amorphous Al2O3, Materials Cloud Archive (2019), doi: 10.24435/materialscloud:2019.0026/v1.
The electronic properties of the oxygen vacancy and interstitial in amorphous Al2O3 are studied via ab initio molecular dynamics simulations and hybrid functional calculations. Our results indicate that these defects do not occur in amorphous Al2O3, due to structural rearrangements which assimilate the defect structure and cause a delocalization of the associated defect levels. The imbalance of oxygen leads to a nonstoichiometric compound in which the oxygen occurs in the form of O2– ions. Intrinsic oxygen defects are found to be unable to trap excess electrons. For low Fermi energies, the formation of peroxy linkages is found to be favored leading to the capture of holes. The relative +2/0 defect levels occur at 2.5 eV from the valence band.
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|10.2 KiB||The relaxed atomic structure of the O-O peroxy linkage induced by the addition of two holes into the bulk model.|
|10.2 KiB||The atomic structure of a defect-free substoichiometric oxide obtained after carrying out MD simulations for the bulk model with the addition of an O2- ion.|
|10.1 KiB||The atomic structure of a defect-free substoichiometric oxide achieved after performing an annealing cycle using MD simulations for the bulk model with an O2- ion removed.|
|10.4 KiB||The atomic structure of the bulk amorphous Al2O3 model constructed through the melt-and-quench method [D. Colleoni, G. Miceli, and A. Pasquarello, Appl. Phys. Lett. 107, 211601 (2015)]. This model contains 160 atoms, with the lattice parameters of 11.47, 11.24, and 12.78 angstrom in the x, y and z direction, respectively.|
|10.2 KiB||The relaxed atomic structure of an O-O peroxy linkage formed upon the insertion of a neutral interstitial oxygen atom. In this configuration, the two O atoms in the peroxy linkage are bonded to different Al atoms.|
|10.2 KiB||The relaxed atomic structure of an O-O peroxy linkage formed upon the insertion of a neutral interstitial oxygen atom. In this configuration, the two O atoms in the peroxy linkage form one bond to the same Al atom.|
|1.3 KiB||Description of the file contents.|
30 May 2019 [This version]