Ab initio study of substitutional nitrogen in GaAs

W. Orellana, A. C. Ferraz

Resultado de la investigación: Contribución a una revistaArtículo

13 Citas (Scopus)

Resumen

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
Volumen78
N.º9
DOI
EstadoPublicada - 26 feb 2001

Áreas temáticas de ASJC Scopus

  • Física y astronomía (miscelánea)

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