Experimental Evidence of Delocalization in Correlated Disordered Superlattices

We studied GaAs–Al0.3Ga0.7As intentionally disordered semiconductor superlattices with and without correlation of the disorder. The structural properties have been characterized by X-ray diffraction. The electronic states of the SL have been studied by photovoltage spectroscopy and compared with theoretical calculation of the miniband structure and transmission coefficient. We observed that delocalization processes take place when the disorder is correlated, confirming the theoretical expectations.