GAAS/ALGAAS MULTIQUANTUM-WELL RESONANT PHOTOREFRACTIVE DEVICES FABRICATED USING EPITAXIAL LIFT-OFF

This letter deals with resonant photorefractive devices fabricated from multiquantum wells of GaAs/Al0.3Ga0.7As and operated in a quantum-confined Stark effect geometry. Details of the processing are presented. Epitaxial lift-off was used to remove the active device from the substrate. Low-temperature Al0.3Ga.07As was used as an insulator to form metal-insulator-semiconductor structures on both sides of the multiquantum wells. Proton implant damage was used to improve the fringe visibility. Photorefractive wave mixing with a diffraction efficiency of approximately 0.03% was demonstrated. The incorporation of a nitride layer between the top electrode and the low-temperature AlGaAs increased the efficiency to 0.5%. The improvement is attributed to a reduction in the conduction of carriers across the low-temperature layer into the electrode.