The controlled disordering of quantum wells using surface oxidation

A new technique has been developed, which allows the controlled, partial disordering of GaAs/AlGaAs multiple quantum wells, using thermal diffusion of aluminium and/or gallium vacancies created by etching the surface oxides. Spectral measurements by photoluminescence and optical absorption indicate that the disordering can result in a blue shift of the effective band edge by up to 40 nm without broadening of the excitonic resonances.