Ab initio study of substitutional nitrogen in GaAs

W. Orellana, A. C. Ferraz

Resultado de la investigación: Contribución a una revistaArtículo

13 Citas (Scopus)


We investigate the atomic geometry, formation energies, and electronic structure of nitrogen occupying both arsenic and gallium sites in GaAs (NAs and NGa) using first-principles total-energy calculations. We find that both neutral defects induce impurity-like empty levels in the band gap acting as acceptors. While NAs shows a s-like a1 level in the middle of the band gap, NGa shows a p-like t2 level close to the bottom of the conduction band. The gap level of NAs gives theoretical support for the experimentally observed band-edge redshift on the GaAsN alloy for a N concentration ∼3%. Strong inward relaxations preserving the Td symmetry characterize the NAs equilibrium geometry in all the charge states investigated. In contrast, NGa exhibits a structural metastability in neutral charge state and Jahn-Teller off-center distortions in negative charge states forming a negative-U center. Formation energies of competing NAs and NGa defects are also discussed.

Idioma originalInglés
Páginas (desde-hasta)1231-1233
Número de páginas3
PublicaciónApplied Physics Letters
EstadoPublicada - 26 feb 2001

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  • Física y astronomía (miscelánea)

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