MAGNITUDE OF THE PIEZOELECTRIC FIELD IN (111)B INYGA1-YAS STRAINED-LAYER QUANTUM-WELLS

The relationship between the magnitude of the piezoelectric field and the degree of lattice constant mismatch is investigated via low-temper ature photoluminescence measurements of the quantum-confined Stark eff ect for a series of (111)B Al0.15Ga0.85As-InyGa1-yAs pseudomorphic qua ntum well heterostructures. The experimental strain-induced electric f ield values agree well with theoretical calculations for indium mole f ractions in the range 0.037 less-than-or-equal-to y less-than-or-equal -to 0.09. In addition, an anomalous saturation of the photoluminescenc e transition energy is observed at values of applied voltage greater t han that required to nullify the piezoelectric field, despite the indi cation from separate electroreflectance measurements that the net elec tric field within the quantum well reverses polarity under similar ele ctrical biasing conditions.