Post growth tailoring of the optical properties of GaAs-AlGaAs multiple quantum wells

The post-growth bandgap engineering of a fifty period multiple quantum well is reported. A controlled blue shift of the band edge is achieved through the deposition of a SiO_x encapsulant followed by rapid thermal annealing giving shifts of up to 16 meV. The expected depth dependence of this process is not observed and thus the blue shifted samples retain clearly resolved room temperature excitonic features and preserve the quantum confined Stark effect.