Publications by Raphaël Butté

Quantifying carbon site switching dynamics in GaN by electron holography

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté

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 ...

2025

Multi-octave bandwidth supercontinuum generation in crystalline Aluminum Nitride-on-sapphire waveguides

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Camille Sophie Brès

Applications such as optical clocks, gas spectroscopy, and optical coherent tomography stand to benefit significantly from the integration of on-chip supercontinuum sources. Materials exhibiting both second- and third-order nonlinearities are particularly ...

International Society for Optical Engineering2025

On the influence of the buffer layer on the optical quality of AlN-on-sapphire epilayers for photonic integrated devices

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Camille Sophie Brès

In the last decade, aluminum nitride (AlN) has proven to be an attractive material for both linear and nonlinear integrated photonics, due to its large transparency window, its low propagation losses and the presence of both second- and third-order nonline ...

SPIE2025

VN-VIn divacancies as the origin of non-radiative recombination centers in InGaN quantum wells

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Yao Chen

In this paper, we investigate the nature of surface defects originating from the high-temperature (HT) GaN buffer and their incorporation into InGaN quantum wells (QWs) grown using the metalorganic vapor phase epitaxy technique. In particular, we conduct a ...

AIP Publishing2025

Identification and thermal healing of focused ion beam-induced defects in GaN using off-axis electron holography

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Yi Wang

Thermal healing of focused ion beam-implanted defects in GaN is investigated by off-axis electron holography in TEM. The data reveal that healing starts at temperatures as low as about 250 degrees C. The healing processes result in an irreversible transiti ...

Iop Publishing Ltd2024

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

Nicolas Grandjean, Raphaël Butté

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 ...

AIP American Institute of Physics2024

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

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté

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 ...

2024

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Duncan Thomas Lindsay Alexander, Pierre Christophe Lottigier, Thomas Fjord Kjaersgaard Weatherley, Davide Maria Di Paola

In this work, we report on the efficiency of single InGaN/GaN quantum wells (QWs) grown on thin (

MDPI2023

Polariton lasing in AlGaN microring with GaN/AlGaN quantum wells

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté

Microcavity polaritons are strongly interacting hybrid light-matter quasiparticles, which are promising for the development of novel light sources and active photonic devices. Here, we report polariton lasing in the UV spectral range in microring resonator ...

AIP Publishing2023

Optical and thermal characterization of a group-III nitride semiconductor membrane by microphotoluminescence spectroscopy and Raman thermometry

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Ian Michael Rousseau

We present the simultaneous optical and thermal analysis of a freestanding photonic semiconductor membrane made from wurtzite III-nitride material. By linking microphotoluminescence spectroscopy with Raman thermometry and other spectroscopic techniques, we ...

Amer Physical Soc2023

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

Nicolas Grandjean, Raphaël Butté, Sebastian Pascal Tamariz Kaufmann, Johann Nicolaï Stachurski, Gordon Jens Callsen

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 ...

SPRINGERNATURE2022

Imaging Nonradiative Point Defects Buried in Quantum Wells Using Cathodoluminescence

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Duncan Thomas Lindsay Alexander, Wei Liu, Wei Liu, Thomas Fjord Kjaersgaard Weatherley

Crystallographic point defects (PDs) can dramatically decrease the efficiency of optoelectronic semiconductor devices, many of which are based on quantum well (QW) heterostructures. However, spatially resolving individual nonradiative PDs buried in such QW ...

AMER CHEMICAL SOC2021

Dark-level trapping, lateral confinement, and built-in electric field contributions to the carrier dynamics in c-plane GaN/AlN quantum dots emitting in the UV range

Nicolas Grandjean, Raphaël Butté, Sebastian Pascal Tamariz Kaufmann

c-plane GaN/AlN quantum dots (QDs) are promising zero-dimensional quantum nanostructures that exhibit single photon emission properties up to room temperature and even above. In this context, it is of prime interest to gain a deeper insight into the recomb ...

AMER INST PHYSICS2021

Ultrafast-nonlinear ultraviolet pulse modulation in an AlInGaN polariton waveguide operating up to room temperature

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Joachim Armand Simonne Ciers, Davide Maria Di Paola

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. These rely on a strong intensity dependent (nonlinear) refractive index capable of modulating optical pulses on sub-picosecond timesca ...

Nature Research2021

Deep traps in InGaN/GaN single quantum well structures grown with and without InGaN underlayers

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Mauro Mosca, Camille Haller

The electrical properties and deep trap spectra were compared for near-UV GaN/InGaN quantum well (QW) structures grown on free-standing GaN substrates. The structures differed by the presence or absence of a thin (110 nm) InGaN layer inserted between the h ...

ELSEVIER SCIENCE SA2020

III-nitride photonic cavities

Nicolas Grandjean, Raphaël Butté

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 ...

WALTER DE GRUYTER GMBH2020

Polariton relaxation and polariton nonlinearities in nonresonantly cw-pumped III-nitride slab waveguides

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Joachim Armand Simonne Ciers, Gordon Jens Callsen

Polariton lasers are mostly based on planar cavities. Here we focus on an alternative configuration with slab waveguide modes strongly coupled to excitons confined in GaN/AlGaN quantum wells. We study experimentally and theoretically polariton relaxation a ...

2020

Toward Bright and Pure Single Photon Emitters at 300 K Based on GaN Quantum Dots on Silicon

Nicolas Grandjean, Raphaël Butté, Sebastian Pascal Tamariz Kaufmann, Johann Nicolaï Stachurski, Kanako Shojiki, Gordon Jens Callsen

Quantum dots (QDs) based on III-nitride semi-conductors are promising for single photon emission at noncryogenic temperatures due to their large exciton binding energies. Here, we demonstrate GaN QD single photon emitters operating at 300 K with g((2)) (0) ...

AMER CHEMICAL SOC2020

Interplay of intrinsic and extrinsic states in pinning and passivation of m-plane facets of GaN n-p-n junctions

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Yi Wang

Intrinsic and extrinsic pinning and passivation of ...

AMER INST PHYSICS2020

Impact of defects on Auger recombination in c-plane InGaN/GaN single quantum well in the efficiency droop regime

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Camille Haller, Yixing Chen, Gwénolé Jean Jacopin, Wei Liu, Thomas Fjord Kjaersgaard Weatherley

We study the impact of non-radiative defects on Auger recombination in c-plane InGaN/GaN single quantum wells (SQWs) in the efficiency droop regime using high injection time-resolved photoluminescence. The defect density in the SQW is controlled by tuning ...

AMER INST PHYSICS2020