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Nicolas Grandjean

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Publications associées (249)

Novel Picosecond Time-Resolved Cathodoluminescence to Probe Exciton Recombination Dynamics in GaN and GaN Based Heterostructures

Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Samuel Sonderegger, Nicolas Grandjean, Laurent Balet, Jelena Ristic, Pierre Michel Corfdir

Cambridge, Cambridge University Press2010

Ultrahigh-Speed AlInN/GaN High Electron Mobility Transistors Grown on (111) High-Resistivity Silicon with F-T=143 GHz

Jean-François Carlin, Nicolas Grandjean, Eric Feltin, Marcus Gonschorek

We report on ultrahigh-speed 80 nm AlInN/GaN high-electron-mobility transistors (HEMTs) grown on (111) high-resistivity silicon substrates. The devices feature a peak measured transconductance g(M) = 415 mS/mm, a maximum current of 1.43 A/mm with a ratio I ...

2010

Proposal and Performance Analysis of Normally Off n(++) GaN/InAlN/AlN/GaN HEMTs With 1-nm-Thick InAlN Barrier

Jean-François Carlin, Nicolas Grandjean, Eric Feltin, Marcus Gonschorek

Design considerations and performance of n(++) GaN/InAlN/AlN/GaN normally off high-electron mobility transistors (HEMTs) are analyzed. Selective and damage-free dry etching of the gate recess through the GaN cap down to a 1-nm-thick InAlN barrier secures p ...

2010

Spin relaxation of free excitons in narrow GaN/AlxGa1-xN quantum wells

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin

By performing pump-probe experiments, we study the relaxation dynamics of spin-polarized excitons in a wurtzite GaN/AlGaN quantum well (QW)grown by metal organic vapor phase epitaxy. The circular degree of polarization of the differential reflectivity sign ...

2010

RF Performance of InAlN/GaN HFETs and MOSHFETs With f(T) X L-G up to 21 GHz . mu m

Jean-François Carlin, Nicolas Grandjean

The RF performance of lattice-matched InAlN/GaN heterostructure field-effect transistors (HFETs) and Al2O3/InAlN/GaN metal-oxide-semiconductor HFETs (MOSHFETs) with varied gate length was evaluated. The current gain cutoff frequency f(T) and the maximum os ...

Institute of Electrical and Electronics Engineers2010

Testing the Temperature Limits of GaN-Based HEMT Devices

Jean-François Carlin, Nicolas Grandjean

The high temperature stability of AlGaN/GaN and lattice-matched InAlN/GaN heterostructure FETs has been evaluated by a stepped temperature test routine under large-signal operation. While AlGaN/GaN high-electron mobility transistors (HEMTs) have failed in ...

2010

Current transport and barrier height evaluation in Ni/InAlN/GaN Schottky diodes

Jean-François Carlin, Nicolas Grandjean

The current-voltage characteristics of the Ni/InAlN/GaN Schottky diodes were measured at various temperatures in the range of 300-700 K. The experimental data were analyzed considering different current-transport mechanisms. From the analysis it follows th ...

2010

Pinning and Depinning of the Polarization of Exciton-Polariton Condensates at Room Temperature

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Marlene Glauser

A room temperature polariton condensate realized in a microcavity with embedded GaN quantum wells emits linearly polarized light at threshold with the plane of polarization pinned to one of the crystallographic axes. With increasing pumping power, a depinn ...

2010

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

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Marlene Glauser

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 ...

2010

Exciton recombination dynamics in a-plane (Al,Ga)N/GaN quantum wells probed by picosecond photo and cathodoluminescence

Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Denis Martin, Samuel Sonderegger, Nicolas Grandjean, Laurent Balet, Tiankai Zhu, Pierre Michel Corfdir

We present a combined low-temperature time-resolved cathodoluminescence and photoluminescence study of exciton recombination mechanisms in a 3.8 nm thick a-plane (Al,Ga)N/GaN quantum well (QW). We observe the luminescence from QW excitons and from excitons ...

American Institute of Physics2010

Bias-dependent absorption coefficient of the absorber section in GaN-based multisection laser diodes

Jean-François Carlin, Nicolas Grandjean, Antonino Francesco Castiglia, Luca Alex Milo Sulmoni

We measure the modal absorption coefficient of the InGaN quantum wells (QWs) in the absorber section of (Al,In)GaN multisection laser diodes as a function of bias voltage and photon energy using optical gain-spectroscopy. In the examined laser diodes, the ...

AIP American Institute of Physics2010

Sputtering of (001)AlN thin films: Control of polarity by a seed layer

Jean-François Carlin, Paul Muralt, Denis Martin, Jürgen Brugger, Nicolas Grandjean, Evgeny Milyutin, Andreea Veronica Savu, Scott Harada

The authors report on the ability to control the polarity of sputter deposited AlN001 thin ﬁlms using seed layers. Reactive sputter deposition leads to N-polarity on any substrate hitherto applied, i.e., Si111, sapphire, SiO2, and polycrystalline metals su ...

American Vacuum Society2010

Emission characteristics of GaN-based blue lasers including a lattice matched Al0.83In0.17N optical blocking layer for improved optical beam quality

Jean-François Carlin, Julien Dorsaz, Gatien Cosendey, Nicolas Grandjean, Eric Feltin, Antonino Francesco Castiglia

We demonstrate room-temperature continuous-wave operation of 425 nm InGaN-based blue laser diodes including a thin Al0.83In0.17N optical blocking layer. Structures are grown on c-plane GaN freestanding substrates with a lattice-matched AlInN layer position ...

AIP American Institute of Physics2010

Probing exciton density of states through phonon-assisted emission in GaN epilayers: A and B exciton contributions

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Massimo Gurioli

A detailed experimental investigation of the phonon-assisted emission in a high-quality c-plane GaN epilayer is presented up to 200 K. By performing photoluminescence and reflectivity measurements, we find important etaloning effects in the phonon-replica ...

2010

AlGaN-Free Blue III-Nitride Laser Diodes Grown on c-Plane GaN Substrates

Jean-François Carlin, Julien Dorsaz, Gatien Cosendey, Nicolas Grandjean, Marco Rossetti, Eric Feltin, Antonino Francesco Castiglia

We report on the fabrication of InGaN-based multiple-quantum-well laser diodes (LDs) emitting at 420 nm. Structures with standard claddings (p-and n-AlGaN), asymmetric claddings (p-GaN and n-AlGaN), and AlGaN-free claddings were grown by metal organic vapo ...

2010

Study of the epitaxial relationships between III-nitrides and M-plane sapphire

Denis Martin, Nicolas Grandjean, Tiankai Zhu

GaN films epitaxially-grown on M-sapphire may have different orientations, either nonpolar and semipolar. In this paper, the different epitaxial relationships are investigated in details thanks to transmission electron microscopy. It is shown that these re ...

2010

AlGaN/GaN HEMT on (111) single crystalline diamond

Denis Martin, Nicolas Grandjean

AlGaN/GaN HEMTs have been fabricated directly on (111) oriented single crystal diamond with 1.3 x 10(13) cm(-2) channel sheet charge density and 731 cm(2)/Vs mobility. 0.2 mu m gate length devices showed 0.73 A/mm maximum drain current density and f(T) and ...

2010

Observation of dodecagon-shape V-defects in GaN/AlInN multiple quantum wells

Jean-François Carlin, Nicolas Grandjean, Eric Feltin, Anas Mouti

The microstructure of GaN(Si)/AlInN multiple quantum wells grown on GaN/Al2O3 (0001) templates by metalorganic vapor-phase epitaxy has been investigated using transmission electron microscopy and associated techniques. Dodecagon-shape V-defects with hexago ...

AIP American Institute of Physics2010

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

Marcel Py, Pierre Stadelmann, Denis Martin, Nicolas Grandjean, Marcus Gonschorek, Anas Mouti, Marco Malinverni

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 ...

2010

Condensation phase diagram of cavity polaritons in GaN-based microcavities: Experiment and theory

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin

The evolution of the polariton condensation threshold (P-thr) under incoherent optical pumping is investigated both theoretically and experimentally over a wide range of temperatures (4-340 K) and exciton-cavity photon detunings (-120-0 meV) in a multiple ...

2010

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