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The assignment of the 78/203meV double acceptor in GaAs to BAs impurity antisite centres.

Zuordnung des 78/203meV Doppelakzeptors in GaAs zu dem BAs Fremdatom-Antisite-Defekt
: Newman, R.C.; Davidson, B.R.; Addinall, R.; Murray, R.; Emmert, J.W.; Wagner, J.; Götz, W.; Roos, G.; Pensl, G.


Materials Science Forum 143-147 (1994), pp.229-234 : Abb.,Lit.
ISSN: 0255-5476
Journal Article
Fraunhofer IAF ()
78/203meV Doppelakzeptor; 78/203meV double acceptor; BAs antisite defect; BAsAntisite-Defekt; GaAs

Ga-rich GaAs shows two levels at (Esubv plus 78 meV) and (Esubv plus 203 meV) due to a He-like double acceptor. The consensus is that the defect responsible is the GasubAs antisite, but IR localized vibrational mode (LVM) measurements have also revealed the presence of BsubAs impurity antisites when the Fermi level EpsilonsubF is above (EsubV plus 203 meV), leading to an ambiguity. New photoluminescence analyses reveal the 78/203 meV defect in LEC GaAs containing boron but not in boron-free Bridgman GaAs. Reversible photo-induced changes of the strengths of the absorption from the electronic 78/203 meV levels and the LVM line are consistent with their assignments to BsubAshigh0, BsubAshigh- and BsubAshigh2- respectively. Combined DLTS measurements, used to determine the concentration of the 78 meV level, and IR measurements led to an estimated effective charge of the BsubAs LVM of Eta about 2.5 e. The BsubAs defect appears to be bistable and to give rise to a resonant mode at 225 cmhig h-1, revealed by Raman scattering, when EtasubF smaller than (EsubV plus 78 meV).