Publications de Camille Haller

Investigation and modeling of the role of interface defects in the optical degradation of InGaN/GaN LEDs

Jean-François Carlin, Nicolas Grandjean, Camille Haller

We investigate the degradation mechanisms of In0.2Ga0.8N/GaN light emitting diodes through combined experimental analysis and simulations. The devices were submitted to constant current stress at 100 mA. Depending on the measuring current level, two degrad ...

2024

III-N Optoelectronic Devices: Understanding the Physics of Electro-Optical Degradation

Jean-François Carlin, Nicolas Grandjean, Camille Haller

III-N optoelectronic devices are of great interest for many applications. Visible emitters (based on InGaN) are widely used in the lighting, display and automotive fields. Ultraviolet LEDs (based on AlGaN) are expected to be widely used for disinfection, m ...

SPIE2023

Defects in III-N LEDs: experimental identification and impact on electro-optical characteristics

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

III-N light-emitting-diodes (LEDs) are subject of intense investigations, thanks to their high efficiency and great reliability. The quality of the semiconductor material has a significant impact on the electro-optical performance of LEDs: for this reason, ...

SPIE-INT SOC OPTICAL ENGINEERING2022

Near ultraviolet photonic integrated lasers based on silicon nitride

Nicolas Grandjean, Rui Ning Wang, Tobias Kippenberg, Camille Haller, Junqiu Liu, Grigorii Likhachev, Andrey Voloshin, Anat Siddharth

Low phase noise lasers based on the combination of III-V semiconductors and silicon photonics are well established in the near-infrared spectral regime. Recent advances in the development of low-loss silicon nitride-based photonic integrated resonators hav ...

AIP Publishing2022

Modeling the electrical characteristic of InGaN/GaN blue-violet LED structure under electrical stress

Jean-François Carlin, Nicolas Grandjean, Camille Haller

The role of deep defects and their physical origin in InGaN/GaN LED are still widely investigated and debated, in particular their impact on the electrical and optical characteristics and on the reliability of the device. In this paper we evaluate the elec ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Deep defects in InGaN LEDs: modeling the impact on the electrical characteristics

Jean-François Carlin, Nicolas Grandjean, Camille Haller

Deep defects have a fundamental role in determining the electro-optical characteristics and in the efficiency of InGaN light-emitting diodes (LEDs). However, modeling their effect on the electrical characteristics of the LED is not straightforward. ...

SPIE-INT SOC OPTICAL ENGINEERING2022

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

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

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 ...

IOP PUBLISHING LTD2021

Effects of quantum-well indium content on deep defects and reliability of InGaN/GaN light-emitting diodes with under layer

Jean-François Carlin, Nicolas Grandjean, Camille Haller

We investigate the density of defects and the degradation rate in InGaN light-emitting diodes having identical dislocation density and epitaxial structure, but different indium content in the quantum well (QW; 12%, 16%, 20%). Our results, based on combined ...

IOP PUBLISHING LTD2021

Modeling the electrical characteristics of InGaN/GaN LED structures based on experimentally-measured defect characteristics

Jean-François Carlin, Nicolas Grandjean, Camille Haller

Defects can significantly modify the electro-optical characteristics of InGaN light-emitting diodes (LEDs); however, modeling the impact of defects on the electrical characteristics of LEDs is not straightforward. In this paper, we present an extensive inv ...

IOP PUBLISHING LTD2021

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

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

Effects of 5 MeV electron irradiation on deep traps and electroluminescence from near-UV InGaN/GaN single quantum well light-emitting diodes with and without InAlN superlattice underlayer

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

The electrical properties, electroluminescence (EL) power output and deep trap spectra were studied before and after 5 MeV electron irradiation of near-UV single-quantum-well (SQW) light-emitting diodes (LED) structures differing by the presence or absence ...

IOP PUBLISHING LTD2020

Effects of InAlN underlayer on deep traps detected in near-UV InGaN/GaN single quantum well light-emitting diodes

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

Two types of near-UV light-emitting diodes (LEDs) with an InGaN/GaN single quantum well (QW) differing only in the presence or absence of an underlayer (UL) consisting of an InAlN/GaN superlattice (SL) were examined. The InAlN-based ULs were previously sho ...

AMER INST PHYSICS2019

InAlN underlaver for near ultraviolet InGaN based light emitting diodes

Jean-François Carlin, Nicolas Grandjean, Mauro Mosca, Camille Haller, Rolf Erni

We report on InAlN underlayer (UL) to improve the efficiency of near ultraviolet (NUV) light emitting diodes (LEDs). While InGaN UL is commonly used in high-efficiency blue LEDs it may absorb light for shorter wavelengths. InAlN lattice-matched to GaN exhi ...

2019

Elucidating the role of the InGaN UL in the efficiency of InGaN based light-emitting diodes

Camille Haller

Blue III-nitride light-emitting diodes (LEDs) are widely used nowadays in solid-state lighting, as white light can be produced by combining yellow phosphors and blue LEDs. This technology has the advantage to have a higher luminous efficiency than incandes ...

EPFL2019

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

Jean-François Carlin, Denis Martin, Nicolas Grandjean, Raphaël Butté, Camille Haller, Gwénolé Jean Jacopin, Wei Liu

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 ...

2018

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

Jean-François Carlin, Denis Martin, Nicolas Grandjean, Raphaël Butté, Camille Haller, Gwénolé Jean Jacopin

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 ...

American Institute of Physics2017

InGaN laser diode with metal-free laser ridge using n(+)-GaN contact layers

Denis Martin, Nicolas Grandjean, Marco Rossetti, Antonino Francesco Castiglia, Marco Malinverni, Camille Haller

We report on InGaN edge emitting laser diodes with a top metal electrode located beside the laser ridge. Current spreading over the ridge is achieved via a highly doped n(+)-type GaN layer deposited on top of the structure. The low sheet resistance of the ...

Iop Publishing Ltd2016

Design and operation of FACT - the first G-APD Cherenkov telescope

Mathieu Ribordy, Camille Haller, Thomas Günther Bretz, Werner Lustermann

The First G-APD Cherenkov Telescope (FACT) is designed to detect cosmic gamma-rays with energies from several hundred GeV up to about 10 TeV using the Imaging Atmospheric Cherenkov Technique. In contrast to former or existing telescopes, the camera of the ...

Iop Publishing Ltd2013

A search for flaring very-high-energy cosmic gamma-ray sources with the L3+C muon spectrometer

Eduardo Sanchez, Horst Vogel, Aurelio Bay, Yu Lei, Jian Zhao, Camille Haller, Liang Sun, Qian Wang, Zhirui Xu, Matthias Weber, Ji Hyun Kim, Werner Lustermann, Xiao Wang, Yifei Guo, Xuan Yang, Zheng Wang

The L3+C muon detector at the CERN electron-positron collider, LEP, is used for the detection of very-high-energy cosmic gamma-ray sources through the observation of muons of energies above 20, 30, 50 and 100 GeV. Daily or monthly excesses in the rate of s ...

Elsevier2006