The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Thierry Bretagnon - One of the best experts on this subject based on the ideXlab platform.
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Transport of indirect excitons in ZnO Quantum Wells.
Optics Letters, 2015Co-Authors: Yuliya Kuznetsova, Leonid Butov, Peristera Andreakou, Thierry Bretagnon, Pierre Lefebvre, Fedor Fedichkin, Eric Calman, Thierry Guillet, Maria Vladimirova, Christian MorhainAbstract:We report on spatially- and time-resolved emission measurements and observation of transport of indirect excitons in ZnO/MgZnO wide single Quantum Wells.
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Optical properties of ZnO/(Zn, Mg)O Quantum Wells
Turkish Journal of Physics, 2014Co-Authors: Thierry BretagnonAbstract:This paper reviews the optical properties of ZnO/(Zn, Mg)O single Quantum Wells grown by molecular beam epitaxy. Both heteroepitaxial Quantum well growth along the polar c-direction and homoepitaxial Quantum well growth on the nonpolar M plane cases are considered. The optical properties of these Quantum Wells are investigated by using re ectance, continuous wave photoluminescence, and time-resolved photoluminescence spectroscopies. The Quantum-con ned Stark e ect dominates the properties of the excitons for polar Quantum Wells. The magnitude of the internal electric eld that is induced by both spontaneous and piezoelectric polarizations is determined by comparing the experimental results with a variational calculation of excitonic energies and lifetimes. For nonpolar Quantum Wells, the optical spectra reveal strong in-plane optical anisotropies, as predicted by the group theory. Moreover, the radiative recombination of free excitons is dominating the Quantum well photoluminescence even at room temperature.
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Excitonic recombination dynamics in non-polar GaN/AlGaN Quantum Wells
Journal of Applied Physics, 2014Co-Authors: Daniel Rosales, Thierry Bretagnon, Bernard Gil, Brahim Guizal, F. Zhang, S. Okur, M. Monarian, Natalia Izyumskaya, Vitaly Avrutin, U. OzgurAbstract:The optical properties of GaN/Al0.15Ga0.85N multiple Quantum Wells are examined in 8K–300K temperature range. Both polarized CW and time resolved temperature-dependent photoluminescence experiment are performed so that we can deduce the relative contributions of the non-radiative and radiative recombination processes. From the calculation of the proportion of the excitonic population having wave vector in the light cone, we can deduce the variation of the radiative decay time with temperature. We find part of the excitonic population to be localized in concert with the report of Corfdir et al. (Jpn. J. Appl. Phys., Part 2 52, 08JC01 (2013)) in case of a-plane Quantum Wells. VC 2014 AIP Publishing LLC.
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Time-resolved photuminescence spectroscopy investigations of nonpolar homoepitaxial ZnO/(Zn,Mg)O Quantum Wells.
2012Co-Authors: Thierry Bretagnon, Bernard Gil, Thierry Guillet, Luc Beaur, Christelle Brimont, J.m. ChauveauAbstract:Time-resolved photuminescence spectroscopy investigations of nonpolar homoepitaxial ZnO/(Zn,Mg)O Quantum Wells.
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Optical investigations of non-polar homo-epitaxial ZnO/(Zn,Mg)O Quantum Wells
2011Co-Authors: Luc Beaur, Thierry Bretagnon, Bernard Gil, Thierry Guillet, Christelle Brimont, J.m. Chauveau, C. MorhainAbstract:Optical investigations of non-polar homo-epitaxial ZnO/(Zn,Mg)O Quantum Wells
Pierre Lefebvre - One of the best experts on this subject based on the ideXlab platform.
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Transport of indirect excitons in ZnO Quantum Wells.
Optics Letters, 2015Co-Authors: Yuliya Kuznetsova, Leonid Butov, Peristera Andreakou, Thierry Bretagnon, Pierre Lefebvre, Fedor Fedichkin, Eric Calman, Thierry Guillet, Maria Vladimirova, Christian MorhainAbstract:We report on spatially- and time-resolved emission measurements and observation of transport of indirect excitons in ZnO/MgZnO wide single Quantum Wells.
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Internal electric field in ZnO/Zn1-xMgxO in single Quantum Wells.
2008Co-Authors: Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Thierry Guillet, Stéphane Faure, Christian MorhainAbstract:We have investigated a series of samples embedding ZnO/(Zn,Mg)O Quantum Wells of different sizes, in wurtzite phase, by using timeresolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The presence of large internal electric fields in these Quantum Wells manifests itself not only through the energies of the optical recombinations, but also through the size dependence of the recombination times. An envelope-function model that includes the variational calculation of the exciton binding energy allows us to determine a value of 0.9 MV/cm for the internal electric field.
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Time-resolved spectroscopy of excitonic transitions in ZnO/(Zn, Mg)O Quantum Wells
2006Co-Authors: Thierry Guillet, Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Christian Morhain, Thierry Taliercio, Xiaodong TangAbstract:We report on the optical spectroscopy of a series of ZnO/(Zn, Mg)O Quantum Wells of different widths, using time-resolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The barriers consist of Zn0.78Mg0.22O layers. The presence of large internal electric fields in these Quantum Wells results in a competition between Quantum confinement and the Quantum confined Stark effect as the Quantum well width is varied. A transition energy lying 0.5 eV below the ZnO excitonic gap was observed for the widest of our Wells. The PL spectra of the wide Quantum Wells were obtained using time-integrated photoluminescence, taking a great care with screening effects induced by their very slow dynamics. The effect of the built-in electric field on the excitonic properties was investigated. The excitonic fine structure is shown to depend strongly on the enhancement or suppression of the exchange interaction as a function of the Quantum well width.
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Time resolved photoluminescence study of ZnO/(Zn,Mg)O Quantum Wells
2005Co-Authors: Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Christian Morhain, Pierre Valvin, Xiaodong TangAbstract:We have investigated a series of samples embedding ZnO/(Zn,Mg)O Quantum Wells of different sizes, in wurtzite phase, by using time-resolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The presence of large internal electric fields in these Quantum Wells manifests itself not only through the energies of the optical recombinations, but also through the size dependence of the recombination times. An envelope-function model that includes the variational calculation of the exciton binding energy allows us to determine a value of 0.9 MV/cm for the internal electric field.
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Photo-induced interband absorption in group-III nitride Quantum Wells
2002Co-Authors: Sokratis Kalliakos, Pierre Lefebvre, Thierry TaliercioAbstract:We solve self-consistently Schrödinger and Poisson equations for GaN/AlGaN Quantum Wells, to analyze the change of optical spectra under high optical excitation. Electric fields of Full-size image ~1 MV/cm or higher are present along the growth axis of such Quantum Wells. The induced separation of electron and hole wave functions reduces the oscillator strength of the ground-state optical transition, whereas those involving excited states give a much larger absorption. In presence of large electron–hole pair densities, we show that the optical density can be either reduced or enhanced, depending on the spectral region involved.
Ya-fei Hao - One of the best experts on this subject based on the ideXlab platform.
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Spin-orbit interaction in multiple Quantum Wells
Journal of Applied Physics, 2015Co-Authors: Ya-fei HaoAbstract:In this paper, we investigate how the structure of multiple Quantum Wells affects spin-orbit interactions. To increase the interface-related Rashba spin splitting and the strength of the interface-related Rashba spin-orbit interaction, we designed three kinds of multiple Quantum Wells. We demonstrate that the structure of the multiple Quantum Wells strongly affected the interface-related Rashba spin-orbit interaction, increasing the interface-related Rashba spin splitting to up to 26% larger in multiple Quantum Wells than in a stepped Quantum well. We also show that the cubic Dresselhaus spin-orbit interaction similarly influenced the spin relaxation time of multiple Quantum Wells and that of a stepped Quantum well. The increase in the interface-related Rashba spin splitting originates from the relationship between interface-related Rashba spin splitting and electron probability density. Our results suggest that multiple Quantum Wells can be good candidates for spintronic devices.
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Interface effect in coupled Quantum Wells
Journal of Applied Physics, 2014Co-Authors: Ya-fei HaoAbstract:This paper intends to theoretically investigate the effect of the interfaces on the Rashba spin splitting of two coupled Quantum Wells. The results show that the interface related Rashba spin splitting of the two coupled Quantum Wells is both smaller than that of a step Quantum well which has the same structure with the step Quantum well in the coupled Quantum Wells. And the influence of the cubic Dresselhaus spin-orbit interaction of the coupled Quantum Wells is larger than that of a step Quantum well. It demonstrates that the spin relaxation time of the two coupled Quantum Wells will be shorter than that of a step Quantum well. As for the application in the spintronic devices, a step Quantum well may be better than the coupled Quantum Wells, which is mentioned in this paper.
Bernard Gil - One of the best experts on this subject based on the ideXlab platform.
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Excitonic recombination dynamics in non-polar GaN/AlGaN Quantum Wells
Journal of Applied Physics, 2014Co-Authors: Daniel Rosales, Thierry Bretagnon, Bernard Gil, Brahim Guizal, F. Zhang, S. Okur, M. Monarian, Natalia Izyumskaya, Vitaly Avrutin, U. OzgurAbstract:The optical properties of GaN/Al0.15Ga0.85N multiple Quantum Wells are examined in 8K–300K temperature range. Both polarized CW and time resolved temperature-dependent photoluminescence experiment are performed so that we can deduce the relative contributions of the non-radiative and radiative recombination processes. From the calculation of the proportion of the excitonic population having wave vector in the light cone, we can deduce the variation of the radiative decay time with temperature. We find part of the excitonic population to be localized in concert with the report of Corfdir et al. (Jpn. J. Appl. Phys., Part 2 52, 08JC01 (2013)) in case of a-plane Quantum Wells. VC 2014 AIP Publishing LLC.
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Time-resolved photuminescence spectroscopy investigations of nonpolar homoepitaxial ZnO/(Zn,Mg)O Quantum Wells.
2012Co-Authors: Thierry Bretagnon, Bernard Gil, Thierry Guillet, Luc Beaur, Christelle Brimont, J.m. ChauveauAbstract:Time-resolved photuminescence spectroscopy investigations of nonpolar homoepitaxial ZnO/(Zn,Mg)O Quantum Wells.
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Optical investigations of non-polar homo-epitaxial ZnO/(Zn,Mg)O Quantum Wells
2011Co-Authors: Luc Beaur, Thierry Bretagnon, Bernard Gil, Thierry Guillet, Christelle Brimont, J.m. Chauveau, C. MorhainAbstract:Optical investigations of non-polar homo-epitaxial ZnO/(Zn,Mg)O Quantum Wells
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Optical investigation of non polar ZnO/(Zn,Mg)O Quantum Wells
physica status solidi (c), 2011Co-Authors: Luc Beaur, Thierry Bretagnon, Bernard Gil, Thierry Guillet, Christelle Brimont, J.m. Chauveau, C. MorhainAbstract:Optical investigation of non polar ZnO/(Zn,Mg)O Quantum Wells
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Internal electric field in ZnO/Zn1-xMgxO in single Quantum Wells.
2008Co-Authors: Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Thierry Guillet, Stéphane Faure, Christian MorhainAbstract:We have investigated a series of samples embedding ZnO/(Zn,Mg)O Quantum Wells of different sizes, in wurtzite phase, by using timeresolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The presence of large internal electric fields in these Quantum Wells manifests itself not only through the energies of the optical recombinations, but also through the size dependence of the recombination times. An envelope-function model that includes the variational calculation of the exciton binding energy allows us to determine a value of 0.9 MV/cm for the internal electric field.
Christian Morhain - One of the best experts on this subject based on the ideXlab platform.
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Transport of indirect excitons in ZnO Quantum Wells.
Optics Letters, 2015Co-Authors: Yuliya Kuznetsova, Leonid Butov, Peristera Andreakou, Thierry Bretagnon, Pierre Lefebvre, Fedor Fedichkin, Eric Calman, Thierry Guillet, Maria Vladimirova, Christian MorhainAbstract:We report on spatially- and time-resolved emission measurements and observation of transport of indirect excitons in ZnO/MgZnO wide single Quantum Wells.
-
Internal electric field in ZnO/Zn1-xMgxO in single Quantum Wells.
2008Co-Authors: Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Thierry Guillet, Stéphane Faure, Christian MorhainAbstract:We have investigated a series of samples embedding ZnO/(Zn,Mg)O Quantum Wells of different sizes, in wurtzite phase, by using timeresolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The presence of large internal electric fields in these Quantum Wells manifests itself not only through the energies of the optical recombinations, but also through the size dependence of the recombination times. An envelope-function model that includes the variational calculation of the exciton binding energy allows us to determine a value of 0.9 MV/cm for the internal electric field.
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Time-resolved spectroscopy of excitonic transitions in ZnO/(Zn, Mg)O Quantum Wells
2006Co-Authors: Thierry Guillet, Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Christian Morhain, Thierry Taliercio, Xiaodong TangAbstract:We report on the optical spectroscopy of a series of ZnO/(Zn, Mg)O Quantum Wells of different widths, using time-resolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The barriers consist of Zn0.78Mg0.22O layers. The presence of large internal electric fields in these Quantum Wells results in a competition between Quantum confinement and the Quantum confined Stark effect as the Quantum well width is varied. A transition energy lying 0.5 eV below the ZnO excitonic gap was observed for the widest of our Wells. The PL spectra of the wide Quantum Wells were obtained using time-integrated photoluminescence, taking a great care with screening effects induced by their very slow dynamics. The effect of the built-in electric field on the excitonic properties was investigated. The excitonic fine structure is shown to depend strongly on the enhancement or suppression of the exchange interaction as a function of the Quantum well width.
-
Time resolved photoluminescence study of ZnO/(Zn,Mg)O Quantum Wells
2005Co-Authors: Thierry Bretagnon, Bernard Gil, Pierre Lefebvre, Christian Morhain, Pierre Valvin, Xiaodong TangAbstract:We have investigated a series of samples embedding ZnO/(Zn,Mg)O Quantum Wells of different sizes, in wurtzite phase, by using time-resolved photoluminescence. The samples were grown by molecular beam epitaxy on ZnO templates, themselves deposited on sapphire substrates. The presence of large internal electric fields in these Quantum Wells manifests itself not only through the energies of the optical recombinations, but also through the size dependence of the recombination times. An envelope-function model that includes the variational calculation of the exciton binding energy allows us to determine a value of 0.9 MV/cm for the internal electric field.
