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Philippe Bugnon

Cette personne n’est plus à l’EPFL

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Publications associées (34)

Bulk and surface band structure of the new family of semiconductors BiTeX (X=I, Br, Cl)

Helmuth Berger, Philippe Bugnon, Marco Grioni, Arnaud Magrez, Oleg Yazyev, Luca Moreschini, Alberto Crepaldi, Simon Karl Moser, Gabriel Albert Autes, Jens Christian Johannsen

We present an overview of the new family of semiconductors BiTeX (X = I, Br, Cl) from the perspective of angle resolved photoemission spectroscopy. The strong band bending occurring at the surface potentially endows them with a large flexibility, as they a ...

Elsevier2015

Momentum and photon energy dependence of the circular dichroic photoemission in the bulk Rashba semiconductors BiTeX (X = I, Br, Cl)

Helmuth Berger, Philippe Bugnon, Marco Grioni, Arnaud Magrez, Oleg Yazyev, Luca Moreschini, Alberto Crepaldi, Gabriel Albert Autes, Cédric Tournier-Colletta, Jens Christian Johannsen

Bulk Rashba systems BiTeX (X = I, Br, Cl) are emerging as important candidates for developing spintronics devices because of the coexistence of spin-split bulk and surface states, along with the ambipolar character of the surface charge carriers. The need ...

American Physical Society2014

Optical properties of BiTeBr and BiTeCl

Helmuth Berger, Philippe Bugnon, Arnaud Magrez, Ana Akrap, Dirk Van der Marel

We present a comparative study of the optical properties-reflectance, transmission, and optical conductivity- and Raman spectra of two layered bismuth-tellurohalides BiTeBr and BiTeCl at 300 and 5 K, for light polarized in the a-b planes. Despite different ...

Amer Physical Soc2014

Unusual Shubnikov-de Haas oscillations in BiTeCl

Helmuth Berger, Philippe Bugnon, Arnaud Magrez

We report measurements of Shubnikov-de Haas oscillations in single crystals of BiTeCl at magnetic fields up to 31 T and at temperatures as low as 0.4 K. Two oscillation frequencies were resolved at the lowest temperatures, F-1 = 65 +/- 4 T and F-2 = 156 +/ ...

Amer Physical Soc2014

Atomic and electronic structure of a Rashba p-n junction at the BiTeI surface

Helmuth Berger, Philippe Bugnon, Marco Grioni, Oleg Yazyev, Gabriel Albert Autes, Cédric Tournier-Colletta

The non-centro-symmetric semiconductor BiTeI exhibits two distinct surface terminations that support spin-split Rashba surface states. Their ambipolarity can be exploited for creating spin-polarized p-n junctions at the boundaries between domains with diff ...

American Physical Society2014

Thermal diffusivity measurements of templated nanocomposite using infrared thermography

Helmuth Berger, Philippe Bugnon, Arnaud Magrez, Manish Sharma

Electrodeposited bismuth telluride (Bi2Te3) nanowires using anodic alumina (AAO) templates show anisotropic thermal properties in a direction parallel and perpendicular to the nanowire/nanochannel axis. The present study reports thermal diffusivity measure ...

Elsevier Science Bv2014

Enhanced low-temperature thermoelectrical properties of BiTeCl grown by topotactic method

Helmuth Berger, Philippe Bugnon, László Forró, Richard Gaal, Arnaud Magrez, Ana Akrap, Jacim Jacimovic, Xavier François Mettan, Sergiy Katrych, Andrea Pisoni

We developed a topotactic strategy to grow BiTeCl single crystals. Structural characterization by means of X-ray diffraction was performed, and the high crystallinity of the material was proven. Measurements of the thermoelectrical coefficients electrical ...

Pergamon-Elsevier Science Ltd2014

Evidence of reduced surface electron-phonon scattering in the conduction band of Bi2Se3 by nonequilibrium ARPES

Helmuth Berger, Philippe Bugnon, Klaus Kern, Marco Grioni, Alberto Crepaldi, Jens Christian Johannsen

The nature of the Dirac quasiparticles in topological insulators calls for a direct investigation of the electron-phonon scattering at the surface. By comparing time-resolved ARPES measurements of the topological insulator Bi2Se3 with different probing dep ...

Amer Physical Soc2013

Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3

Helmuth Berger, Philippe Bugnon, Klaus Kern, Marco Grioni, Alberto Crepaldi

We exploit time- and angle-resolved photoemission spectroscopy to determine the evolution of the out-of-equilibrium electronic structure of the topological insulator Bi2Se3. The response of the Fermi-Dirac distribution to ultrashort IR laser pulses has bee ...

Amer Physical Soc2012

Giant Ambipolar Rashba Effect in the Semiconductor BiTeI

Helmuth Berger, Philippe Bugnon, Klaus Kern, Marco Grioni, Oleg Yazyev, Luca Moreschini, Alberto Crepaldi, Simon Karl Moser, Gabriel Albert Autes, Naunidh Singh Virk, Cédric Tournier-Colletta

We observe a giant spin-orbit splitting in the bulk and surface states of the noncentrosymmetric semiconductor BiTeI. We show that the Fermi level can be placed in the valence or in the conduction band by controlling the surface termination. In both cases, ...

Amer Physical Soc2012

Structural and electronic implications for carrier injection into organic semiconductors

Philippe Bugnon, Mauro Castellani

We report on the structural and electronic interface formation between ITO (indium-tin-oxide) and prototypical organic small molecular semiconductors, i.e., CuPc (copper phthalocyanine) and alpha-NPD (N,N'-di(naphtalen-1-yl)-N,N'-diphenyl-benzidine). In pa ...

Springer Verlag2009

An ester-substituted iridium complex for efficient vacuum-processed organic light-emitting diodes

Philippe Bugnon, Michael Graetzel, Mohammad Khaja Nazeeruddin, Libero Zuppiroli, Rosario Scopelliti, Stéphane Suarez

An orange-red-emitting iridium complex (N958) was prepared, and its photophysical and device-based characteristics were investigated. Despite N958 displaying quite poor photophysical properties in solution (acetonitrile), organic light-emitting diode (OLED ...

2009

Sublimation Not an Innocent Technique: A Case of Bis-Cyclometalated Iridium Emitter for OLED

Philippe Bugnon, Michael Graetzel, Mohammad Khaja Nazeeruddin, Libero Zuppiroli, Rosario Scopelliti, Stéphane Suarez

Isomerization of a neutral bis-cyclometalated iridium(III) complex has been observed for the first time during the preparation of vacuum-processed organic light-emitting devices (OLEDs) and reproduced in solution. Isolation of the isomer revealed a cis org ...

2008

Efficient blue light-emitting diodes based on a classical "push-pull" architecture molecule 4,4 prime -di-(2-(2,5- dimethoxyphenyl)ethenyl)-2,2 prime -bipyridine

Philippe Bugnon, Michael Graetzel, Mohammad Khaja Nazeeruddin, Libero Zuppiroli, Rosario Scopelliti, Detlef Berner, Mauro Castellani, Filippo de Angelis

A novel, highly blue luminescent molecule containing donor and acceptor groups, 4,4 prime -di-(2-(2,5-dimethoxyphenyl)ethenyl)-2,2 prime -bipyridine, that shows photoluminescence emission at 450 nm with 43% quantum yield is designed and synthesized. Time d ...

Royal Society of Chemistry2006

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