Publications by Raphaël Butté

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We report on the current properties of Al1-x InxN (x approximate to 0.18) layers lattice- matched ( LM) to GaN and their specific use to realize nearly strain- free structures for photonic and electronic applications. Following a literature survey of the g ...

We observe a room-temperature low-threshold transition to a coherent polariton state in bulk GaN microcavities in the strong-coupling regime. Nonresonant pulsed optical pumping produces rapid thermalization and yields a clear emission threshold of 1 mW, co ...

Off-axis electron holography is utilized to identify point defect reactions and quantify their dynamics by probing the time and temperature dependence of the Fermi level upon annealing. The methodology is illustrated using implanted carbon (C) in GaN, wher ...

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 ...

The mechanisms contributing to experimental quality factors of shortwavelength (lambda = 440-480 nm) III-nitride on silicon one-dimensional photonic crystal cavities were quantified. Fluctuations in fundamental and first-order cavity mode wavelength and qu ...

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 ...

Owing to their wide direct bandgap tenability, III-nitride (III-N) compound semiconductors have been proven instrumental in the development of blue light-emitting diodes that led to the so-called solid-state lighting revolution and blue laser diodes that a ...

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 ...

Very narrow spontaneous emission (Deltalambda similar to 0.5 nm), corresponding to a quality factor Q in excess of 800, has been obtained under continuous-wave excitation at room temperature with an AlInN/GaN monolithic microcavity. The structure is made o ...

The insertion of an InGaN underlayer (UL) is known to strongly improve the performance of InGaN/GaN quantum well (QW) based blue light emitting diodes (LEDs). However, the actual physical mechanism responsible for it is still unclear. We thus conduct a sys ...

The origin of efficiency droop in state-of-the-art quality In GaN/GaN and GaN/AlGaN quantum wells (QWs) grown on various crystal planes is studied by means of time-resolved photoluminescence spectroscopy associated with a precise determination of the QW ca ...

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 ...

We report a study of self-assembled GaN/AlN quantum dots (QDs) grown by metalorganic vapor phase epitaxy. We have investigated the impact of the AlN template quality on the nucleation of QDs obtained by the so-called Stranski-Krastanov growth mode transiti ...

We propose to use lattice-matched AlInN/GaN to replace the Al(Ga)N/GaN material system for III-nitride Bragg reflectors, despite the poor material quality of AlInN reported until very recently. We report an improvement of AlInN material that allowed for su ...

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 ...

GaN/AlGaN and InGaN/GaN quantum wells (QWs) are investigated as the active region for room-temperature strong exciton-photon coupling in high-quality AlInN/(Al)GaN microcavities (MCs). Angular resolved photoluminescence (PL) measurements performed on an Al ...

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 ...

The growth by hydride vapor phase epitaxy (HVPE) of high quality thin GaN layers (d=8 mu m) on c-plane sapphire substrates with dislocation densities lower than 2x10(8) cm(-2) is demonstrated using a two-step process similar to that of metal organic vapor ...

Intersubband (lSB) optical absorption in different nitride-based heterostructures grown by metal-organic chemical vapour deposition (MOCVD) is reported. The role of indium in AlInN/GaN multi-quantum wells (MQWs) is investigated. At high concentration (15%) ...

The authors report on the micron scale characterization of a monolithic GaN microcavity (MC) with lattice matched AlInN/GaN distributed Bragg reflectors by means of a microtransmission setup. This technique allows extracting very high quality factors (Q up ...

Raphaël Butté

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Current status of AlInN layers lattice-matched to GaN for photonics and electronics

Room-temperature polariton lasing in semiconductor microcavities

Quantifying carbon site switching dynamics in GaN by electron holography

Phase diagram of a polariton laser from cryogenic to room temperature

Quantification of scattering loss of III-nitride photonic crystal cavities in the blue spectral range

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

III-nitride photonic cavities

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

Lattice-matched distributed Bragg reflectors for nitride-based vertical cavity surface emitting lasers

Burying non-radiative defects in InGaN underlayer to increase InGaN/GaN quantum well efficiency

Enhancement of Auger recombination induced by carrier localization in InGaN/GaN quantum wells

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

Strain relaxation of AlN epilayers Stranski-Krastanov GaN/AlN quantum dots grown by organic vapor phase epitaxy

Progresses in III-nitride distributed Bragg reflectors and microcavities using AlInN/GaN materials

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

Impact of inhomogeneous excitonic broadening on the strong exciton-photon coupling in quantum well nitride microcavities

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

High quality thin GaN templates grown by hydride vapor phase epitaxy on sapphire substrates

Nitride-based heterostructures grown by MOCVD for near- and mid-infrared intersubband transitions

Impact of disorder on high quality factor III-V nitride microcavities