Ab initio study of substitutional nitrogen in GaAs

W. Orellana, A. C. Ferraz

Resultado de la investigación: Article

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 originalEnglish
Páginas (desde-hasta)1231-1233
Número de páginas3
PublicaciónApplied Physics Letters
Volumen78
N.º9
DOI
EstadoPublished - 26 feb 2001

Huella dactilar

nitrogen
energy of formation
defects
geometry
arsenic
metastable state
preserving
gallium
conduction bands
electronic structure
impurities
symmetry
energy

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Citar esto

Orellana, W. ; Ferraz, A. C. / Ab initio study of substitutional nitrogen in GaAs. En: Applied Physics Letters. 2001 ; Vol. 78, N.º 9. pp. 1231-1233.
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Ab initio study of substitutional nitrogen in GaAs. / Orellana, W.; Ferraz, A. C.

En: Applied Physics Letters, Vol. 78, N.º 9, 26.02.2001, p. 1231-1233.

Resultado de la investigación: Article

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AB - 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.

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