ENHANCED STARK SHIFT IN GAAS ALGAAS STEP QUANTUM-WELL UNDER AN APPLIED ELECTRIC-FIELD/

Theoretical calculations of the quantum confined Stark shift for the f irst heavy hole exciton (hh1-e1) in step quantum well are given. A sig nificant change in Stark shift is achieved in specially stepped potent ial shape, which is more than two times larger than the conventional r ectangular quantum well. The structure has the advantage of a large ch ange in absorption, which is one of the best candidates for the optica l modulators utilizing the quantum confined Stark effect (QCSE) in GaA s/AlGaAs. Relations between QCSE and stepped structure are discussed i n the optimization for large Stark shift.