M. Nakayama et al., PHOTOREFLECTANCE AND RESONANT RAMAN-SCATTERING OF ABOVE-BARRIER TRANSITIONS IN A GAAS ALGAAS SUPERLATTICE/, JPN J A P 2, 34, 1994, pp. 80-82
We have investigated the energy states above the barrier potential (ab
ove-barrier states) in a (GaAs)(10)/(Al0.3Ga0.7As)(10) superlattice us
ing photoreflectance and resonant-Raman scattering spectroscopies. The
energies of the photoreflectance signals observed in the above-barrie
r region higher than the band-gap energy of Al0.3Ga0.7As just agree wi
th the peak energies of the resonant-Raman profiles of the longitudina
l-optical phonons. From the miniband energies calculated by an effecti
ve-mass approximation, we conclude that the photoreflectance signals a
nd the resonant Raman profiles are caused by the transitions associate
d with the above-barrier states at the mini-Brillouin-zone edge.