Published online by Cambridge University Press: 28 February 2011
We have studied the photoreflectance spectrum at 300K from a GaAs/In0.5 Ga0.5p (ordered) single quantum well fabricated by atomic layer epitaxy. Comparison of the energies of the observed intersubband and barrier transitions with an envelope function model calculation yields a valence band offset of 350 ± 20 meV.