ANALYSIS OF STRAINED INGAAS INGAASP SINGLE QUANTUM-WELLS USING ROOM-TEMPERATURE PHOTOREFLECTANCE/

Room temperature photoreflectance (PR) has been performed on five nomi nally 90 Angstrom wide ln(1-x)Ga(x)As undoped single quantum well (QW) structures in In0.77Ga0.23As0.49P0.51 barriers, lattice matched to an InP substrate. The nominal QW Ga composition varies between x = 0.47 and x = 0.68, corresponding to tensile strains between zero and 1.47%, respectively. Room temperature photoluminescence measurements are als o performed on the same position on the sample as the PR, Allowed and forbidden interband QW transition energies, given by least-squares fit ting to the PR, are found to agree well with theoretical predictions b ased on an effective mass formalism, including excitonic binding energ ies and quantum-confined Stark effects. In achieving this agreement, v alues for the QW composition, thickness and band offset are determined by refining their nominal values. The conduction band offsets are fou nd to range from 0.35 to 0.14 for tensile strains between zero and 1.4 0%. The energies of the ground state light-and heavy-hole QW transitio ns increase roughly linearly with tensile strain.