Disorder characterization by means of radiatively coupled quantum wells

We present an approach to the investigation of structural disorder in quantum wells (QWs) based on the reflectivity line shape analysis of radiatively coupled QWs. In the case of anti-Bragg structures, as a consequence of the condition of destructive interference, the reflectivity spectrum is indeed extremely sensitive to vertical disorder. We exploit the method in the case of GaAs/AlGaAs structures and we demonstrate the possibility of measuring differences in the excitonic transition energies of the two QWs as small as 10% of the inhomogeneous broadening.