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Raphaël Butté

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Publications associées (105)

Tailoring the light-matter coupling in anisotropic microcavities: Redistribution of oscillator strength in strained m-plane GaN/AlGaN quantum wells

Gatien Cosendey, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Marlene Glauser, Georg Rossbach, Munise Nevin Cobet

We present a comprehensive study of the anisotropic optical properties of nonpolar GaN/AlGaN multiple quantum wells intentionally designed to act as an active region of a planar microcavity operating in the strong-coupling regime. The strain induced by the ...

2011

LIGHT-EMITTING DIODES Solid-state lighting on glass

Nicolas Grandjean, Raphaël Butté

Nature Publishing Group2011

Spin relaxation of free excitons in narrow GaN/AlxGa1-xN quantum wells

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin

By performing pump-probe experiments, we study the relaxation dynamics of spin-polarized excitons in a wurtzite GaN/AlGaN quantum well (QW)grown by metal organic vapor phase epitaxy. The circular degree of polarization of the differential reflectivity sign ...

2010

Pinning and Depinning of the Polarization of Exciton-Polariton Condensates at Room Temperature

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Marlene Glauser

A room temperature polariton condensate realized in a microcavity with embedded GaN quantum wells emits linearly polarized light at threshold with the plane of polarization pinned to one of the crystallographic axes. With increasing pumping power, a depinn ...

2010

Anomalous composition dependence of the band gap pressure coefficients in In-containing nitride semiconductors

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Marlene Glauser

The pressure-induced changes in the electronic band structures of In-containing nitride alloys, InxGa1-xN and InxAl1-xN are examined experimentally as well as by ab initio calculations. It is found that the band gap pressure coefficients, dE(g)/dp, exhibit ...

2010

Probing exciton density of states through phonon-assisted emission in GaN epilayers: A and B exciton contributions

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Massimo Gurioli

A detailed experimental investigation of the phonon-assisted emission in a high-quality c-plane GaN epilayer is presented up to 200 K. By performing photoluminescence and reflectivity measurements, we find important etaloning effects in the phonon-replica ...

2010

Condensation phase diagram of cavity polaritons in GaN-based microcavities: Experiment and theory

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin

The evolution of the polariton condensation threshold (P-thr) under incoherent optical pumping is investigated both theoretically and experimentally over a wide range of temperatures (4-340 K) and exciton-cavity photon detunings (-120-0 meV) in a multiple ...

2010

Towards room temperature electrically pumped blue vertical cavity surface emitting lasers

Jean-François Carlin, Alexei Altoukhov, Gatien Cosendey, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Gabriel Christmann, Antonino Francesco Castiglia

The authors report on strategies to achieve lasing in electrically driven vertical cavity surface emitting lasers at room temperature, namely the improvement of the quality factor of a microcavity suited for electrical injection, the use of a ZnO contact t ...

Ieee2009

Tailoring the strong coupling regime in III-nitride based microcavities for room temperature polariton laser applications

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Gabriel Christmann

We report on the properties of III-nitride based microcavities (MCs) operating in the strong coupling regime (SCR) up to room temperature. We first discuss why this class of materials is well suited to investigate the physics of cavity polaritons, which ar ...

Wiley-Blackwell2009

Phase diagram of a polariton laser from cryogenic to room temperature

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Gabriel Christmann

The signature of the strong-coupling regime is unambiguously evidenced in a GaN-based microcavity (MC) above the polariton lasing threshold P-thr at room temperature through the observation of the upper polariton branch. The MC system exhibits a renormaliz ...

2009

High reflectivity airgap distributed Bragg reflectors realized by wet etching of AlInN sacrificial layers

Jean-François Carlin, Alexei Altoukhov, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Antonino Francesco Castiglia

The authors report on the achievement of a vertically oriented three pair airgap/GaN distributed Bragg reflector realized by controlled oxidation and wet-chemical etching of AlInN sacrificial layers. Microreflectivity measurements exhibit high peak reflect ...

2009

Quantum confinement dependence of the energy splitting and recombination dynamics of A and B excitons in a GaN/AlGaN quantum well

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Massimo Gurioli

We report the observation of well-resolved A and B excitonic resonances in the reflectivity spectra of a wedged GaN/AlGaN quantum well (QW) with 5% Al content in the barriers for different well thicknesses. For the thicker well cases, the energy splitting ...

2009

Al0.83In0.17N lattice-matched to GaN used as an optical blocking layer in GaN-based edge emitting lasers

Jean-François Carlin, Alexei Altoukhov, Gatien Cosendey, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Antonino Francesco Castiglia

Nitride-based blue laser diode structures with either Al0.83In0.17N/Al0.07Ga0.93N or Al0.87In0.13N bottom claddings have been fabricated and compared to standard structures including solely Al0.07Ga0.93N bottom claddings. Lasing emission at 415 nm is achie ...

2009

GaN-based laser diodes including a lattice-matched Al0.83In0.17N cladding layer

Jean-François Carlin, Gatien Cosendey, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Antonino Francesco Castiglia

Nitride blue lasers including an AlInN cladding lattice matched to GaN were fabricated. Lasing at 415nm is observed at 300K with a threshold current density of 7.5kA/cm(2) and a peak power of 140mW at 1.2A. (C) 2009 Optical Society of America ...

Ieee2009

Room temperature polariton lasing in a GaN/AlGaN multiple quantum well microcavity

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Gabriel Christmann

The authors report room temperature polariton lasing at lambda similar to 345 nm in a hybrid AlInN/AlGaN multiple quantum well microcavity (MQW-MC) containing a GaN/AlGaN MQW active region, i.e., the achievement under nonresonant optical excitation of cohe ...

2008

High quality nitride based microdisks obtained via selective wet etching of AlInN sacrificial layers

Jean-François Carlin, Alexei Altoukhov, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Antonino Francesco Castiglia

The authors report a technique for selective wet chemical etching of an AlInN sacrificial layer lattice-matched to GaN for the fabrication of air-gap photonic structures. It is used to demonstrate high quality factor (Q) microdisk cavities. Whispering gall ...

2008

Biexciton kinetics in GaN quantum wells: Time-resolved and time-integrated photoluminescence measurements

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Massimo Gurioli

We report on the experimental achievement of narrow ultraviolet excitonic and biexcitonic emission from GaN/AlGaN quantum wells. The very large biexciton binding energy (up to 12 meV) inhibits thermalization between the two species allowing to study the re ...

2008

Spontaneous polarization buildup in a room-temperature polariton laser

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Gabriel Christmann

We observe the buildup of strong (similar to 50%) spontaneous vector polarization in emission from a GaN-based polariton laser excited by short optical pulses at room temperature. The Stokes vector of emitted light changes its orientation randomly from one ...

2008

Impact of quantum confinement and quantum confined Stark effect on biexciton binding energy in GaN/AlGaN quantum wells

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Massimo Gurioli

We report on time-resolved photoluminescence measurements carried out along the thickness gradient of two types of GaN/AlGaN quantum wells with low Al content in the barriers (5% and 9%, respectively). A reduction of the biexciton binding energy with incre ...

2008

Complex behavior of biexcitons in GaN quantum dots due to a giant built-in polarization field

Nicolas Grandjean, Raphaël Butté, Dobri Simeonov

In-depth optical spectroscopic studies of single polar GaN/AlN quantum dots (QDs) grown by molecular beam epitaxy are carried out by means of low-temperature microphotoluminescence. Luminescence linewidths as low as 700 mu eV are obtained allowing thorough ...

2008

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