Electric-field dependence of interband transitions in In0.53Ga0.47As/In0.52Al0.48As single quantum wells by room-temperature electrotransmittance

Room-temperature electrotransmittance has been used in order to investigate the interband excitonic transitions in a 250-Å-thick In0.53Ga0.47As/In0.52Al0.48As single-quantum-well system as a function of an externally applied electric field. Parity forbidden transitions, involving conduction-band states with quantum numbers up to n=5, which become more pronounced at high electric fields were observed. The ground-state and the forbidden transitions showed a significant red shift due to the quantum confined Stark effect. A comparison with previously reported results on thinner InGaAs/InAlAs quantum wells indicated that the wide-well sample exhibits the largest shift, as expected from theory. Despite the appreciable Stark shift, the rather large, field-induced linewidth broadening and the relatively low electric field at which the ground-state exciton is ionized poses limitations on using this wide-quantum-well system for electro-optic applications.