Optical properties and thermal transport of carriers in (Zn,Cd)Se-ZnSe heterostructures |
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Authors: | L Aigouy B Gil O Briot T Cloitre N Briot R L Aulombard M Averous |
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Affiliation: | (1) Groupe d’Etudes des Semiconducteurs, Case Courrier 074, Université de Montpellier II, place Eugène Bataillon, 34095, 05 Montpellier, Cedex, France |
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Abstract: | We report a detailed optical study of ZnSe-based graded index separate confinement heterostructures. These structures were
grown by metalorganic vapor phase epitaxy and are composed of either one or two Zn0.79Cd0.21Se central well(s) embedded between two ZnCdSe barriers which cadmium composition varies linearly from 5% near the wells to
0% at the end of the barriers. 2K photoreflectance and reflectivity experiments allow the observation of excitonic transitions
involving the third electron and heavy hole confined states. The temperature dependence of the photoluminescence lines under
in-well resonant excitation conditions (Eexc = 2.661 eV) shows that the thermal quenching of the photoluminescence line is ruled by nonradiative recombinations on defects
localized at the heterointerfaces at low temperature and by the thermal escape of the minority carriers at higher temperatures.
Under above-barrier excitation conditions (Eexc=3.814 eV), the temperature dependence of the photoluminescence line from the well shows a strong influence of the mechanism
of diffusion of the carriers from the barriers to the well. |
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Keywords: | Diffusion Franz-Keldysh oscillations GRIN-SCH photoluminescence photoreflectance thermal escape |
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