MODELING AND ANALYSIS OF PHOTOMODULATED REFLECTANCE AND DOUBLE-CRYSTAL X-RAY-DIFFRACTION MEASUREMENTS OF TENSILELY STRAINED INGAAS INGAASP QUANTUM-WELL STRUCTURES/

Room temperature photomodulated reflectance (PR) and double crystal x- ray diffraction (DCXRD) measurements have been performed on a series o f tensilely strained InxGa1-xAs multiple quantum well (QW) laser struc tures, with In0.80Ga0.20As0.43P0.57 barriers, which are lattice-matche d to an InP substrate. Seven samples are studied, with nominal QW Ln c omposition varying between x = 0.533 and 0.316, corresponding to biaxi al tensile strains between 0% and 1.5%, respectively. The DCXRD measur ements provide accurate information on composition, strain and layer t hickness, while the PR yields the energies of both allowed and forbidd en critical point interband QW transitions, and how these vary with st rain, particularly the transitions between the ground-state conduction band and heavy/light hole valence band levels. A three-band effective mass formalism is used to model the QW transitions and very good agre ement with the PR measurements is obtained once excitonic binding ener gies, and the quantum confined Stark effect are taken into account. (C ) 1998 American Institute of Physics.