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(167) Production(s) de LEFEBVRE P.
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Polarized emission of GaN/AlN quantum dots : single dot spectroscopy and symmetry-based theory 
Auteur(s): Bardoux Richard, Guillet T. , Gil B., Lefebvre P., Bretagnon T., Taliercio T., Rousset S., Semond F.
(Article) Publié:
Physical Review B, vol. 77 p.235315 (2008)
Texte intégral en Openaccess : 
Ref HAL: hal-00261181_v3
Ref Arxiv: 0803.0899
DOI: 10.1103/PhysRevB.77.235315
WoS: 000257289500082
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
63 Citations
Résumé: We report micro-photoluminescence studies of single GaN/AlN quantum dots grown along the (0001) crystal axis by molecular beam epitaxy on Si(111) substrates. The emission lines exhibit a linear polarization along the growth plane, but with varying magnitudes of the polarization degree and with principal polarization axes that do not necessarily correspond to crystallographic directions. Moreover, we could not observe any splitting of polarized emission lines, at least within the spectral resolution of our setup (1 meV). We propose a model based on the joint effects of electron-hole exchange interaction and in-plane anisotropy of strain and/or quantum dot shape, in order to explain the quantitative differences between our observations and those previously reported on, e.g. CdTe- or InAs-based quantum dots.
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Unusual dynamics of time-resolved emission from wide-band gap quantum dots.
Auteur(s): Lefebvre P.
Conférence invité: Workshop on Advances in Physics and Applications of Low-Dimensional Systems (Brazilia, BR, 2007-07-09)
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Contribution of long lived metastable states to the PL of InP dots in indirect band-gap barrier layers
Auteur(s): Seguin Robert, Guillet T., Taliercio T., Lefebvre P., Bretagnon T., Zhang X.B., Ryou J.-H., Dupuis R.D.
(Article) Publié:
The European Physical Journal Applied Physics, vol. 37 p.15 (2007)
Texte intégral en Openaccess : 
Ref HAL: hal-00389970_v1
DOI: 10.1051/epjap:2007006
WoS: 000243790800003
Exporter : BibTex | endNote
2 Citations
Résumé: We report continuous wave and time resolved photoluminescence studies of self-assembled InP quantum dots grown by metalorganic chemical vapor deposition. The quantum dots are embedded into indirect band-gap In0.5Al0.5P layers or In0.5Al0.3Ga0.2P layers with a conduction band line-up close to the direct-to-indirect crossover. As revealed by photoluminescence spectra, efficient interdiffusion of species from the barrier layers produces (Al,In)P or (Al,Ga,In)P-dots. This interdiffusion creates potential barriers that are repulsive for electrons of X valleys around the QDs. Both samples show a fast exponential decay component with a time constant between 0.5 and 0.7 ns. In addition, the sample with indirect band gap matrix shows a slow non-exponential time-decay, which is still visible after more than 100 µs. The fast component is attributed to direct recombination of electron-hole pairs in the dots whilst the slow component, which follows a power law t^-0.75 results from recombination of holes in the dots and electrons in metastable states around the dots.
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Radiative lifetime in wurtzite GaN/AlN quantum dots.
Auteur(s): Bardoux Richard, Bretagnon T., Guillet T., Lefebvre P., Taliercio T., Valvin P., Gil B., Semond F., Grandjean N., Damilano B., Dussaigne Amélie, Massies Jean
Conference: International Symposium on Blue Laser and Light Emitting Diodes (ISBLED06) (Montpellier, FR, 2006-05-15)
Actes de conférence: Physica Statu Solidi (c), vol. 4 p.183 (2007)
Texte intégral en Openaccess :
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Synthes de nanofils de ZnO dans des matériaux poreux ordonnés: experience et simulation moléculaire
Auteur(s): Tedenac Jean-Claude, Mezy Aude., Bretagnon T., Coasne Benoit, Gerardin Corine, Lefebvre P., Pichon Bernard, Ravot Didier, Suwanboon S., Tichit Didier
Conference: Matériaux 2006 (, FR, 2007-11-13)
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Time-resolved photoluminescence and optically stimulated luminescence measurements of picosecond-excited SrS:Ce,Sm phosphor
Auteur(s): Ravotti F., Benoit D., Lefebvre P., Valvin P., Vaillé J.-R., Dusseau L., Fesquet J., Gasiot J.
(Article) Publié:
Journal Of Applied Physics, vol. 102 p.123102 (2007)
Ref HAL: hal-00327469_v1
DOI: 10.1063/1.2822474
WoS: 000251987600002
Exporter : BibTex | endNote
10 Citations
Résumé: Doubly activated alkaline-earth phosphors are known to present luminescent and charge-storage properties. In this work, we investigate the photoluminescence (PL) and the optically stimulated luminescence (OSL) of the SrS:Ce,Sm phosphor by means of time-resolved spectroscopy with excitation laser pulses of 2 ps duration. By comparing the PL measurements obtained with direct UV excitation and the OSL experiments performed using infrared wavelength, it was possible to measure a charge conversion lifetime of about 2.5±1 ns. A luminescence lifetime of 36±1 ns has also been found. These measurements are presented and discussed in connection with applications where the speed of the SrS:Ce,Sm luminescence is a crucial parameter
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Morphology control of ZnO nanomaterials using double hydrophilis block polymers
Auteur(s): Tedenac Jean Claude, Mezy Aude., Gerardin Corine, Tichit Didier, Suwanboon S., Ravot Didier, Bretagnon T., Lefebvre P.
Conference: 2007 MRS fall meeting (Boston, US, 2007-11-26)
Actes de conférence: proceedings, vol. p.1 (2007)
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