Coupling induced enhancement of nonradiative and supression of radiative recombination in superlattices
| Autor: | Dieter Bimberg, Jürgen Christen, M. Krahl |
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| Rok vydání: | 1990 |
| Předmět: |
Physics
Condensed matter physics Exciton Superlattice Biophysics General Chemistry Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter Physics Biochemistry Atomic and Molecular Physics and Optics Radiative transfer Spontaneous emission Quantum efficiency Wave function Recombination Quantum well |
| Zdroj: | Journal of Luminescence. 45:176-180 |
| ISSN: | 0022-2313 |
| Popis: | In quantum wells (QW) the recombination rates are strongly enhanced due to the localization-induced increased overlap of the carrier wave functions, providing a dramatic reduction in lifetime. This effect is confirmed here in detail for GaInAs/InP MOVPE grown uncoupled QWs having different well widths Lz. A new model of two-dimensional excitons which correctly accounts for the anisotropy of the problem quantitatively predicts the radiative lifetime reduction in agreement with experiment. These localization induced QW features get increasingly lost with progressive coupling of adjacent QWs in a multiple quantum well structure. As a model system, GaAs MQWs having constant Lz but varying barrier widths LB are investigated. A drastic increase of carrier decay rate with decreasing LB is observed. The increased total recombination rate together with the observed decrease of quantum efficiency can be consistently explained by an increase of nonradiative recombination: a theoretical analysis based on the superlattice wavefunctions shows that the nonradiative recombination centers are localized at the QW heterointerfaces and not in the barriers. In addition detailed analysis reveals the expected reduction of radiative recombination rate. |
| Databáze: | OpenAIRE |
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