Accueil >
Production scientifique
(322) Production(s) de GIL B.
|
|
Nonlinear spectral hole-burning of the intraband transition at 1.55 μm in GaN/AlN quantum dots
Auteur(s): Nguyen Dac-Trung, Tchernycheva M., Julien F. H., Monroy E., Gil B., Cassabois G.
Conference: International Workshop on Nitride semiconductors (IWN2012) (Sapporo, JP, 2012-10-15)
Ref HAL: hal-00744476_v1
Exporter : BibTex | endNote
Résumé: GaN/AlN quantum dots are semiconductor nanostructures where the huge conduction band offset of 1.75 eV leads to intraband transitions at exceptionnaly short wavelengths compared to III-As semiconductor materials. For specific quantum dot dimensions, it was shown that the absorption spectrum covers the optical communication spectral range. The ultrafast relaxation dynamics observed for these materials motivates the development of opto-electronic devices, and especially ultrafast switches. However, a detailed insight into the microscopic processes governing the relaxation dynamics is still missing although of fundamental importance for the understanding and the optimization of the devices operation. In particular, there is no study of the homogeneous broadening which drives the saturation properties of GaN/AlN quantum dots-devices. In this paper, we present homogeneous linewidth measurements by means of the nonlinear optical technique of spectral hole-burning. Spectrally-resolved pump-probe experiments with cw-lasers allow us to characterize the coherence relaxation dynamics down to 5K by resolving the homogeneous linewidth in an ensemble of GaN/AlN quantum dots. The differential transmission measured at 5K for a TM-polarized pump shows a pronounced bleaching with an amplitude of 2x10-4 on a background signal of 5x10-5. According to the selection rules of the s-pz intraband transition in GaN/AlN QDs, we attribute the photoinduced increase of the probe transmission to the partial saturation of the quantum dots by the pump laser, and we deduce a homogeneous linewidth of 15 meV at 5K. We find that the differential transmission signal scales like the square-root of the incident pump power, thus revealing the importance of electron-electron scattering in the population relaxation dynamics. As a matter of fact, we find that the population relaxation from the pz excited state is predominantly governed by Auger-type processes whereas optical phonon emission only plays a minor role, even if it may contribute to secondary processes during the carrier cascade to the fundamental s state via intermediate confined states.
|
|
|
Optical properties of a hybrid nitride-ZnO microcavity.
Auteur(s): Lefebvre P., Brimont C., Guillet T., Bretagnon T., Gil B., Valvin P., Médard François-Régis, Mihailovic Martine, Zúñiga-Pérez Jesús, Leroux Mathieu, Semond Fabrice, Bouchoule Sophie
(Affiches/Poster)
SPIE-OPTO-Photonic West. "Gallium Nitride Materials & Devices VII". (San Francisco, US), 2012-01-21
|
|
|
The calculation of semi polar orientations for wurtzitic heterostructures:application to nitrides and oxides
Auteur(s): Bigenwald Pierre, Gil B., Benharrats F, Zitouni K., Kadri A.
(Article) Publié:
Semiconductor Science And Technology, vol. 27 p.024009 (2012)
Texte intégral en Openaccess :
|
|
|
Excitonic states and their wave functions in anisotropic materials: a computation using the finite element method and its application to AlN
Auteur(s): Gil B., Felbacq D., Guizal B., Bouchitté Guy
(Article) Publié:
Physica Status Solidi B, vol. 249 p.455 (2012)
Texte intégral en Openaccess :
|
|
|
Exciton binding energy in chalcopyrite semiconductors
Auteur(s): Gil B., Felbacq D., Chichibu Shigefusa
(Article) Publié:
-Physical Review B Condensed Matter And Materials Physics (1998-2015), vol. 85 p.075205 (2012)
|
|
|
Excitonic parameters of GaN studied by time-of-flight spectroscopy
Auteur(s): V. Shubina T., A. Toropov A., Pozina G., P. Bergman J., M. Glazov M., Gippius Nikolay A., Disseix Pierre, Leymarie Joël, Gil B., Monemar Bo
(Article) Publié:
Applied Physics Letters, vol. 99 p.101108 (2011)
Texte intégral en Openaccess :
|
|
|
Delay and distortion of slow light pulses by excitons in ZnO
Auteur(s): Shubina T. V., Glasov M.M., Gippius Nikolay A., Toropov A.A., Lagarde David, Disseix Pierre, Leymarie Joël, Gil B., Pozina G., P. Bergman J., Monemar B.
(Article) Publié:
-Physical Review B Condensed Matter And Materials Physics (1998-2015), vol. 84 p.075202 (2011)
Texte intégral en Openaccess :
Ref HAL: hal-00633626_v1
DOI: 10.1103/PhysRevB.84.075202
WoS: 000412130700005
Exporter : BibTex | endNote
17 Citations
Résumé: Distortion of light pulses in ZnO caused by both bound and free excitons is demonstrated by time-of-flight spectroscopy. Numerous lines of bound excitons dissect the pulse spectrum and induce slowdown of light propagation around the dips. Exciton-polariton resonances determine the overall pulse delay, which approaches 1.6 ns at 3.374 eV for a 0.3 mm propagation length, as well as the pulse curvature in the time-energy plane and its attenuation. Analysis of cw and time-resolved data yields the excitonic parameters inherent for bulk ZnO. A discrepancy is found between these bulk parameters and those given by surface-probing techniques.
|