Resonant Raman study of intrinsic defect modes in electron- and neutron-irradiated GaAs
1987; American Physical Society; Volume: 35; Issue: 5 Linguagem: Inglês
10.1103/physrevb.35.2205
ISSN1095-3795
Autores Tópico(s)Thin-Film Transistor Technologies
ResumoWe report the results of a resonant Raman study of GaAs samples which contain \ensuremath{\sim}${10}^{17}$--${10}^{18}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ intrinsic defects that have been introduced by either electron or neutron irradiation. We observe several defect-related modes, two of which we identify as local modes of an intrinsic defect, most likely an As vacancy. In the vicinity of the ${E}_{0}$ transition we observe enhancements of these modes that are more dispersive than the enhancement of the TO-phonon scattering. We explain these observations phenomenologically with a fourth-order perturbation theory involving elastic scattering of either an electron or a hole by a defect. The theory predicts that strongly dispersive enhancement can occur for vibrational modes that involve enhanced motion of atoms in the immediate vicinity of a defect.
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