Publications de Dobri Simeonov

Time-resolved cathodoluminescence on polychromatic light emitting (In,Ga)N quantum wells grown on (11-22) GaN facets

Jean-François Carlin, Benoît Marie Joseph Deveaud, Jean-Daniel Ganière, Nicolas Grandjean, Eric Feltin, Dobri Simeonov, Pierre Michel Corfdir

We present a low-temperature time-resolved cathodoluminescence study on (In,Ga)N/GaN quantum wells grown on the (11-22) facets of non-coalesced ELO-GaN. Taking advantage of the quantum confined Stark effect, such structures have been proposed as promising ...

V C H Publishers, Suite 909, 220 E 23Rd St, New York, Ny 10010 Usa2011

Synthesis and optical investigation of single polar GaN/AlN quantum dots

Dobri Simeonov

Over the past few decades, III-V nitrides have attracted much attention due to the possibility to realize high efficiency optoelectronic devices covering all the UV and visible part of the light spectrum. However, the device fabrication has gone much faste ...

EPFL2009

Quantum confinement dependence of the energy splitting and recombination dynamics of A and B excitons in a GaN/AlGaN quantum well

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

We report the observation of well-resolved A and B excitonic resonances in the reflectivity spectra of a wedged GaN/AlGaN quantum well (QW) with 5% Al content in the barriers for different well thicknesses. For the thicker well cases, the energy splitting ...

2009

Temperature mapping of Al0.85In0.15N/AlN/GaN high electron mobility transistors through micro-photoluminescence studies

Jean-François Carlin, Marcel Py, Nicolas Grandjean, Eric Feltin, Dobri Simeonov, Marcus Gonschorek

Crack-free lattice-matched Al0.85In0.15N/GaN heterostructures were grown on sapphire substrates with barrier thicknesses up to 100 nm which exhibit very high polarization-induced electron sheet density (>2.5 x 10(13) cm(-2)) located at the heterointerface. ...

2009

Complex behavior of biexcitons in GaN quantum dots due to a giant built-in polarization field

Nicolas Grandjean, Raphaël Butté, Dobri Simeonov

In-depth optical spectroscopic studies of single polar GaN/AlN quantum dots (QDs) grown by molecular beam epitaxy are carried out by means of low-temperature microphotoluminescence. Luminescence linewidths as low as 700 mu eV are obtained allowing thorough ...

2008

High quality nitride based microdisks obtained via selective wet etching of AlInN sacrificial layers

Jean-François Carlin, Alexei Altoukhov, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Antonino Francesco Castiglia

The authors report a technique for selective wet chemical etching of an AlInN sacrificial layer lattice-matched to GaN for the fabrication of air-gap photonic structures. It is used to demonstrate high quality factor (Q) microdisk cavities. Whispering gall ...

2008

Impact of quantum confinement and quantum confined Stark effect on biexciton binding energy in GaN/AlGaN quantum wells

Jean-François Carlin, Jacques Levrat, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Massimo Gurioli

We report on time-resolved photoluminescence measurements carried out along the thickness gradient of two types of GaN/AlGaN quantum wells with low Al content in the barriers (5% and 9%, respectively). A reduction of the biexciton binding energy with incre ...

2008

Biexciton kinetics in GaN quantum wells: Time-resolved and time-integrated photoluminescence measurements

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

We report on the experimental achievement of narrow ultraviolet excitonic and biexcitonic emission from GaN/AlGaN quantum wells. The very large biexciton binding energy (up to 12 meV) inhibits thermalization between the two species allowing to study the re ...

2008

Current status of AlInN layers lattice-matched to GaN for photonics and electronics

Jean-François Carlin, Marcel Py, Julien Dorsaz, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Sylvain Nicolay, Mauro Mosca, Dobri Simeonov, Gabriel Christmann, Antonino Francesco Castiglia, Marcus Gonschorek

We report on the current properties of Al1-x InxN (x approximate to 0.18) layers lattice- matched ( LM) to GaN and their specific use to realize nearly strain- free structures for photonic and electronic applications. Following a literature survey of the g ...

2007

Efficient current injection scheme for nitride vertical cavity surface emitting lasers

Jean-François Carlin, Julien Dorsaz, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Antonino Francesco Castiglia

The authors report the realization of InGaN/GaN light emitting diodes (LEDs) with an electrical injection design suitable for vertical cavity surface emitting lasers. Controlled oxidation of an AlInN interlayer lattice matched to GaN allows confining the i ...

2007

Blue lasing at room temperature in high quality factor GaN/AlInN microdisks with InGaN quantum wells

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Mauro Mosca, Dobri Simeonov, Tiankai Zhu, Antonino Francesco Castiglia

The authors report on the achievement of optically pumped III-V nitride blue microdisk lasers operating at room temperature. Controlled wet chemical etching of an AlInN interlayer lattice matched to GaN allows forming inverted cone pedestals. Whispering ga ...

2007

Narrow UV emission from homogeneous GaN/AlGaN quantum wells

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

The authors report on the achievement of narrow ultraviolet emission using GaN/AlGaN quantum wells grown by metal organic vapor phase epitaxy. The origin of the inhomogeneous broadening of the emission is explained by means of micro-photoluminescence and a ...

2007

Strain relaxation of AlN epilayers Stranski-Krastanov GaN/AlN quantum dots grown by organic vapor phase epitaxy

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

We report a study of self-assembled GaN/AlN quantum dots (QDs) grown by metalorganic vapor phase epitaxy. We have investigated the impact of the AlN template quality on the nucleation of QDs obtained by the so-called Stranski-Krastanov growth mode transiti ...

2007

Impact of disorder on high quality factor III-V nitride microcavities

Jean-François Carlin, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov, Gabriel Christmann

The authors report on the micron scale characterization of a monolithic GaN microcavity (MC) with lattice matched AlInN/GaN distributed Bragg reflectors by means of a microtransmission setup. This technique allows extracting very high quality factors (Q up ...

2006

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

Jean-François Carlin, Marc Ilegems, Nicolas Grandjean, Raphaël Butté, Eric Feltin, Dobri Simeonov

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 ...

2006