Modulated resonant Raman and photoluminescence spectroscopy of Bragg confined asymmetric coupled quantum wells

Electronic Bragg mirrors were used to confine carriers at energy levels above the barrier height in asymmetric coupled quantum wells. Two classes of above barrier states were resolved by using photoluminescence, photoluminescence excitation and modulated resonant Raman spectroscopy. The first class is Bragg confined levels that are highly localized in the asymmetric quantum wells region and are red shifted when locally excited electric field is generated in the asymmetric coupled quantum well region. The second class of levels that extend mainly above the reflectors is not shifted when the locally excited field is generated. This phenomenon is due to the smaller confinement of the extended states in the asymmetric quantum well region.