Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5424778 | Surface Science | 2009 | 6 Pages |
Abstract
In this work, first-principles modeling techniques are used to investigate the mechanism(s) of adsorption of molecular oxygen on the GaAs(0Â 0Â 1)-(2Â ÃÂ 4) surface. The reaction of adsorption was modeled using ab-initio molecular dynamics at constant temperature for two thermal regimes, i.e. 300Â K and 680Â K, respectively. The resulting adsorbate configurations were relaxed using density functional theory and the adsorption energies were subsequently computed. Our results suggest a dominant mechanism of adsorption described by molecular dissociation, followed by oxygen insertion in the Ga-As bonds, bridging Ga-O-As chemical bonds. The electronic properties of the clean reconstructed GaAs(0Â 0Â 1) surface and the ones obtained after O2 adsorption were computed. It is found that for the most stable adsorbate configuration, where oxygen is incorporated in a Ga-O-As unit, the associated density of electronic states is free of defect levels within the GaAs band gap region.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
M. Scarrozza, G. Pourtois, M. Houssa, M. Caymax, M. Meuris, M.M. Heyns, A. Stesmans,