Photoluminescence study of carrier dynamics and recombination in a strained InGaAsP/InP multiple-quantum-well structure (original) (raw)
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IEEE Journal of Photovoltaics, 2017
The carrier recombination dynamics of In-GaP/InGaAsP quantum wells are reported for the first time. By studying the photoluminescence (PL) and time-resolved PL decay of InGaP/InGaAsP multiple-quantum-well(MQW) heterostructure samples, it is demonstrated that InGaP/InGaAsP MQWs have very low non-radiative recombination rate and high radiative efficiency compared to the control InGaP sample. Along with the analyses of PL emission spectrum and external quantum efficiencies, it suggests that this is due to small confinement potentials in the conduction band but high confinement potentials in the valence band. These results explain several features found in InGaP/InGaAsP MQW solar cells previously.
Analysis of strained InGaAs/InGaAsP single quantum wells using room temperature photoreflectance
Semiconductor Science and Technology, 1998
Room temperature photoreflectance (PR) has been performed on five nominally 90Å wide In 1−x Ga x As undoped single quantum well (QW) structures in In 0.77 Ga 0.23 As 0.49 P 0.51 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 also performed on the same position on the sample as the PR. Allowed and forbidden interband QW transition energies, given by least-squares fitting to the PR, are found to agree well with theoretical predictions based on an effective mass formalism, including excitonic binding energies and quantum-confined Stark effects. In achieving this agreement, values for the QW composition, thickness and band offset are determined by refining their nominal values. The conduction band offsets are found to range from 0.35 to 0.14 for tensile strains between zero and 1.40%. The energies of the ground state lightand heavy-hole QW transitions increase roughly linearly with tensile strain.