Conclusive evidence for miniband dispersion in the photoreflectance of a GaAs/Ga0.74Al0.26As coupled multiple-quantum-well structure

Conclusive evidence for miniband dispersion of the fundamental heavy- and light-hole to conduction-subband transitions of a GaAs/${\mathrm{Ga}}_{0.74}$ ${\mathrm{Al}}_{0.26}$As coupled multiple quantum well has been obtained from the photoreflectance features, i.e., energies as well as relative phases and amplitudes, at 77 K. The experimental energies are in excellent agreement with a Bastard-model calculation while the relative amplitudes and phases can be evaluated from the influence of an electric field on two coupled wells.