Publications de Nicolas Grandjean

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.

Y III-nitride quantum dots (QDs) are a promising system actively studied for their ability to maintain single photon emission up to room temperature. Here, we report on the evolution of the emission properties of self-assembled GaN/ AlN QDs for temperature ...

We report on a practical method for developing InGaN-based edge emitting laser diodes of cavity length down to 45 mu m. Samples consisting of one uncoated cleaved facet and one etched facet coated with a high-reflectivity (HR) dielectric distributed Bragg ...

We present the technology and performance of InAlN/AlN/GaN MOS HEMTs with gate insulation and surface passivation using ZrO2 or HfO2. About 10-nm-thick high-k dielectrics were deposited by MOCVD before the ohmic contact processing. Plasma pretreatment allo ...

We report strong exciton-photon coupling at room temperature in a hybrid high quality bulk 3 lambda/2 GaN cavity with a bottom lattice-matched AlInN/AlGaN distributed Bragg reflector through angle-resolved polarized photoluminescence (PL). Coupling of the ...

The effect of thermal annealing on In0.25Ga0.75N/GaN quantum wells grown by molecular beam epitaxy at 550 degrees C is investigated. A strong increase in the 300 K photoluminescence (PL) intensity is observed for samples annealed at 880 degrees C, while de ...

We present a comprehensive study of AlN growth on Si(111) substrate by gas source molecular beam epitaxy with ammonia as nitrogen precursor in the high temperature range. We first demonstrate that the observation of the silicon 7 x 7 surface reconstruction ...

We report a thorough study of the growth of self-assembled GaN/AlN quantum dots (QDs). These QDs were grown on sapphire substrates using the Stranski-Krastanov (SK) growth mode by means of low-pressure metal organic vapor phase epitaxy. The influence of th ...

Laser action with low threshold average pump power density (similar to 50 W. cm(-2)) at room temperature is reported for a crack-free planar vertical cavity surface emitting laser (VCSEL) structure based on a bottom lattice-matched AllnN/GaN distributed Br ...

Blue light-emitting diodes based on III-nitride semiconductors are nowadays widely used for solid-state lighting. They exhibit impressive figures of merit like an internal quantum efficiency close to 100%. This value is intriguing when considering the high ...

We present a butt-coupled InGaN fiber Bragg grating (FBG) semiconductor laser diode operating below 400 nm in the single-mode emission regime. This compact coherent laser source exhibits an intrinsic linewidth of 14 kHz in the near-UV range and a side-mode ...

High mobility Al0.28Ga0.72N/GaN two-dimensional electron gas (2DEG) is achieved on ( 111) oriented single crystal diamond substrate. The surface morphology of the epilayer is free of cracks thanks to the use of an AlN interlayer for strain relaxation. The ...

We measure the charge carrier recombination coefficients of InGaN quantum wells by analyzing the dynamical properties of (Al,In)GaN laser diodes emitting in the violet spectral range. Relaxation oscillations and turn-on delays are fitted to a rate equation ...

Near-lattice-matched GaN/AlInN quantum wells are investigated by means of contactless electroreflectance (CER) and temperature-dependent photoluminescence (PL). Large Stokes shifts, up to 400 meV, between PL peak energies and CER resonances are identified. ...

The electron optical phase contrast probed by electron holography at n-n+ GaN doping steps is found to exhibit a giant enhancement, in sharp contrast to the always smaller than expected phase contrast reported for p-n junctions. We unravel the physical ori ...

We optimized the far-field emission pattern of one-dimensional photonic crystal nanobeams by modulating the nanobeam width, forming a sidewall Bragg cross-grating far-field coupler. By setting the period of the cross-grating to twice the photonic crystal p ...

Full control over the density and emission properties of GaN quantum dots (QDs) should be feasible, provided that the growth proceeds in the Stranski-Krastanov (SK) growth mode. In this work, we derive the phase diagram for GaN QD formation on AlN by NH3-m ...

Room temperature electron mobility of 1170 cm(2)/V s is obtained in an undoped, lattice-matched, Al0.82In0.18N/GaN field-effect transistor heterostructure, while keeping a high (2.6 +/- 0.3)x10(13) cm(-2) electron gas density intrinsic to the Al0.82In0.18N ...

Forward and reverse leakage currents in GaN/InGaN multi-quantum well light-emitting diodes (LEDs) are caused by reactive-ion etching (RIE) damages during device patterning. A method to recover the damaged surfaces, based on a chemical etch in KOH: ethylene ...

The authors have studied InxGa1-xN/GaN (x approximate to 15%) quantum wells (QWs) using atomic force microscopy (AFM) and picosecond time resolved cathodoluminescence (pTRCL) measurements. They observed a contrast inversion between monochromatic CL maps co ...

Recent studies demonstrated that the performance of InGaN/GaN quantum well (QW) light emitting diodes (LEDs) can be significantly improved through the insertion of an InGaN underlayer (UL). The current working hypothesis is that the presence of the UL redu ...

Nicolas Grandjean

Chattez avec Graph Search

Single photon emission and recombination dynamics in self-assembled GaN/AlN quantum dots

Short cavity InGaN-based laser diodes with cavity length below 300 mu m

Technology and performance of InAlN/AlN/GaN HEMTs with gate insulation and current collapse suppression using ZrO2 or HfO2

Room-temperature polariton luminescence from a bulk GaN microcavity

Thermal annealing of molecular beam epitaxy-grown InGaN/GaN single quantum well

AlN grown on Si(111) by ammonia-molecular beam epitaxy in the 900-1200 degrees C temperature range

Stranski-Krastanov GaN/AlN quantum dots grown by metal organic vapor phase epitaxy

Blue lasing at room temperature in an optically pumped lattice-matched AlInN/GaN VCSEL structure

GaN surface as the source of non-radiative defects in InGaN/GaN quantum wells

Sub-20 kHz low-frequency noise near ultraviolet butt-coupled fiber Bragg grating external cavity laser diode

High-Mobility AlGaN/GaN Two-Dimensional Electron Gas Heterostructure Grown on (111) Single Crystal Diamond Substrate

Recombination coefficients of GaN-based laser diodes

Built-in electric field and large Stokes shift in near-lattice-matched GaN/AlInN quantum wells

Origin of giant enhancement of phase contrast in electron holography of modulation-doped n-type GaN

Far-field coupling in nanobeam photonic crystal cavities

Density control of GaN quantum dots on AlN single crystal

High electron mobility lattice-matched AlInN/GaN field-effect transistor heterostructures

Suppression of leakage currents in GaN-based LEDs induced by reactive-ion etching damages

High spatial resolution picosecond cathodoluminescence of InGaN quantum wells

Defect incorporation in In-containing layers and quantum wells: experimental analysis via deep level profiling and optical spectroscopy