Publications de Denis Martin | EPFL Graph Search

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

Nicolas Grandjean, Jean-François Carlin, Raphaël Butté, Denis Martin, Hua Zhang, Ching-Wen Shih

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 ...

2019

Broadened Bandwidth Amplified Spontaneous Emission from Blue GaN-Based Short-Cavity Superluminescent Light-Emitting Diodes

Nicolas Grandjean, Jean-François Carlin, Raphaël Butté, Denis Martin, Hua Zhang, Ching-Wen Shih

We report broad bandwidth blue superluminescent light-emitting diodes (SLEDs) based on a short-cavity active region. The dependencies of amplified spontaneous emission (ASE) output power and gain bandwidth on cavity length were investigated in devices whos ...

2019

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

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

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

Nicolas Grandjean, Denis Martin, Sebastian Pascal Tamariz Kaufmann

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 ...

Elsevier2017

Critical thickness of GaN on AlN: impact of growth temperature and dislocation density

Nicolas Grandjean, Denis Martin, Pirouz Sohi

Critical thickness and strain relaxation of c-plane GaN layers grown by molecular beam epitaxy on AlN were studied as a function of growth temperature and threading dislocation density (TDD). For this purpose we used AlN/sapphire templates and AlN single c ...

2017

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

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

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

Stabilisation of the gravity structure of the Romanesque Abbey of Payerne Switzerland

Eugen Brühwiler, Denis Martin

2017

Backward diodes using heavily Mg-doped GaN growth by ammonia molecular-beam epitaxy

Nicolas Grandjean, Marco Malinverni, Denis Martin, Hironori Okumura

We grew heavily Mg-doped GaN using ammonia molecular-beam epitaxy. The use of low growth temperature (740 degrees C) allows decreasing the incorporation of donor-like defects (

Amer Inst Physics2016

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

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

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

Low p-type contact resistance by field-emission tunneling in highly Mg-doped GaN

Nicolas Grandjean, Denis Martin, Hironori Okumura

Mg-doped GaN with a net acceptor concentration (NA-ND) in the high 10 19 cm(-3) range was grown using ammonia molecular-beam epitaxy. Electrical properties of NiO contact on this heavily doped p-type GaN were investigated. A potential-barrier height of 0.2 ...

Amer Inst Physics2016