Resonant Raman scattering and photoluminescence at theE0band gap of carbonhyphen;doped AlAs

摘要

Carbonhyphen;doped AlAs grown by solid source molecular beam epitaxy has been studied by Raman and photoluminescence spectroscopy. Doping levels exceeding 2times;1019cmminus;3have been obtained using a heated graphite filament as the carbon source. For excitation just above the AlAsE0bandhyphen;gap energy radiative recombination is observed across that band gap, which involves nonthermalized photogenerated electrons occupying the Ggr;hyphen;conductionhyphen;band minimum rather than the lowest indirectXminima. Raman spectra excited in resonance with theE0band gap show a holehyphen;plasmonhyphen;longitudinalhyphen;opticalhyphen;phonon coupling similar to that found inphyphen;type GaAs. Resonantly excited Raman spectra further reveal a vibrational mode at bartil;635 cmminus;1, which is assigned to the local vibrational mode of theCAsacceptor in AlAs.