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Comparison of strong coupling regimes in bulk GaAs, GaN and ZnO semiconductor microcavities
Auteur(s): Faure Stephane, Guillet T., Lefebvre P., Bretagnon T., Gil B.
(Article) Publié:
Physical Review B, vol. 78 p.235323 (2008)
Texte intégral en Openaccess :
Ref HAL: hal-00327759_v1
Ref Arxiv: 0810.1811
DOI: 10.1103/PhysRevB.78.235323
WoS: 000262245400086
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
49 Citations
Résumé: Wide bandgap semiconductors are attractive candidates for polariton-based devices operating at room temperature. We present numerical simulations of reflectivity, transmission and absorption spectra of bulk GaAs, GaN and ZnO microcavities, in order to compare the particularities of the strong coupling regime in each system. Indeed the intrinsic properties of the excitons in these materials result in a different hierarchy of energies between the valence-band splitting, the effective Rydberg and the Rabi energy, defining the characteristics of the exciton-polariton states independently of the quality factor of the cavity. The knowledge of the composition of the polariton eigenstates is central to optimize such systems. We demonstrate that, in ZnO bulk microcavities, only the lower polaritons are good eigenstates and all other resonances are damped, whereas upper polaritons can be properly defined in GaAs and GaN microcavities.
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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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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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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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Morphology Control of ZnO Nanomaterials using Double Hydrophilic Block Copolymers
Auteur(s): Mezy Aude, Ravot Didier, Gerardin Corine, Tichit Didier, Tedenac Jean Claude, Bretagnon T., Lefebvre P.
Conference: MRS Fall Meeting (Boston, US, 2005-12-01)
Actes de conférence: Materials Research Society Symposium Proceedings, vol. 901 p.Rb15-05.1 (2006)
Ref HAL: hal-00389989_v1
Exporter : BibTex | endNote
Résumé: Highly crystalline zinc oxide (ZnO) nanomaterials are synthesized using a seeded growth sol-gel method. In order to control the morphology and the organization of the ZnO nanomaterials, a double hydrophilic block copolymer has been introduced during the seeded growth synthesis: the Polyacrylic acid-Polyacrylamide (PAA-PAM). Depending on the amount of PAA-PAM copolymers, different morphologies were obtained, such as ZnO nanostructured spheres or flat hexagonal crystals. Thus, systematic studies have been done to investigate the influence of the copolymer addition on ZnO nanomaterial morphologies and explain the mechanisms of the morphological modifications.
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