Publications de Laurent Syavoch Bernard

Thermal coarsening of individual titanate nanowires and their assemblies: Surface vs. bulk diffusion

Luca Rossi, László Forró, Xavier Berdat, Massimo Spina, Endre Horvath, Laurent Syavoch Bernard, Sergiy Katrych

The thermal coarsening of titanate nanowires was investigated from room temperature to 1000 degrees C by AFM, SEM, XRD and Raman spectroscopy. Phase transformation kinetics and the external morphology were studied in two configurations: i) as individual an ...

2020

Cyan titania nanowires: Spectroscopic study of the origin of the self-doping enhanced photocatalytic activity

László Forró, Richard Gaal, Arnaud Magrez, Alla Arakcheeva, Bálint Náfrádi, Xavier Berdat, Jacim Jacimovic, Massimo Spina, Endre Horvath, Laurent Syavoch Bernard, Péter Szirmai

We report a detailed spectroscopic study of Ti3+ self-doped TiO2 nanowires prepared by high temperature annealing of the protonated titanate nanowires (TiONW) in hydrogen atmosphere. Hydrogenation causes a color change from white to cyan and a major increa ...

Elsevier2017

Self-biased reconfigurable graphene stacks for terahertz plasmonics

Julien Perruisseau-Carrier, Mihai Adrian Ionescu, Arnaud Magrez, Clara-Fausta Moldovan, Laurent Syavoch Bernard, Santiago Capdevila Cascante

The gate-controllable complex conductivity of graphene offers unprecedented opportunities for reconfigurable plasmonics at terahertz and mid-infrared frequencies. However, the requirement of a gating electrode close to graphene and the single 'control knob ...

Nature Publishing Group2015

Fabrication process and characterization of suspended graphene membranes for RF NEMS capacitive switches

Mihai Adrian Ionescu, Clara-Fausta Moldovan, Wolfgang Amadeus Vitale, Laurent Syavoch Bernard, Pankaj Sharma

The fabrication of a Nanoelectromechanical System (NEMS) capacitive switch consisting of a suspended multilayer graphene membrane, doubly clamped on a coplanar waveguide (CPW) is presented and its RF performance is evaluated. The scattering parameters are ...

Elsevier2015

Room-Temperature Negative Differential Resistance in Graphene Field Effect Transistors: Experiments and Theory

Mihai Adrian Ionescu, Arnaud Magrez, Laurent Syavoch Bernard, Antonios Bazigos, Pankaj Sharma

In this paper we demonstrate experimentally and discuss the negative differential resistance (NDR) in dual-gated graphene field effect transistors (GFETs) at room temperature for various channel lengths, ranging from 200 nm to 5 mu m. The GFETs were fabric ...

Amer Chemical Soc2015

Graphene Negative Differential Resistance Circuit With Voltage-Tunable High Performance at Room Temperature

Mihai Adrian Ionescu, Arnaud Magrez, Laurent Syavoch Bernard, Antonios Bazigos, Pankaj Sharma

We propose, fabricate, and experimentally demonstrate a circuit based on graphene field-effect transistors (GFETs) showing enhanced negative differential resistance (NDR) characteristics at room temperature. The proposed graphene NDR (GNDR) circuit consist ...

Institute of Electrical and Electronics Engineers2015

Negative Differential Resistance in Top-Gated Chemical Vapor Deposition Grown Graphene Transistors

Mihai Adrian Ionescu, Arnaud Magrez, Laurent Syavoch Bernard, Antonios Bazigos, Pankaj Sharma

2015

Graphene negative differential resistance (GNDR) circuit with enhanced performance at room temperature

Mihai Adrian Ionescu, Arnaud Magrez, Laurent Syavoch Bernard, Antonios Bazigos, Pankaj Sharma

We propose and experimentally demonstrate a novel circuit based on graphene FETs (GFETs) showing excellent negative differential resistance (NDR) characteristics at room temperature. The proposed GNDR circuit exploits a closed loop connection of 1-GFET wit ...

IEEE2015

Graphene : from Growth to Devices

Laurent Syavoch Bernard

We report a full study of graphene synthesis by CVD on Cu surface. Two CVD methods have been developed. The first is a static one, which yields monolayer of graphene at low pressure of methane in 3 minutes at 1000 C. The second one is an equimolar method w ...

EPFL2015

Microengineered CH3NH3PbI3 Nanowire/Graphene Phototransistor for Low-Intensity Light Detection at Room Temperature

László Forró, Richard Gaal, Arnaud Magrez, Bálint Náfrádi, Massimo Spina, Endre Horvath, Laurent Syavoch Bernard, Mario Joe Lehmann, Eric Joseph Bonvin

The first hybrid phototransistors are reported where the performance of a network of photoactive CH3NH3PbI3 nanowires is enhanced by CVD-grown monolayer graphene. These devices show responsivities as high as ≈2.6 × 106 A W- ...

2015

High-yield, in-situ fabrication and integration of horizontal carbon nanotube arrays at the wafer scale for robust ammonia sensors

Mihai Adrian Ionescu, Laurent Syavoch Bernard, Hoël Maxime Guérin, Elizabeth Buitrago Godinez

This paper reports the successful experimental demonstration of the localized growth of horizontal, dense carbon nanotube (CNT) arrays in situ and at the wafer scale. The selectivity and directionality of the CNT catalytic growth process along with the ade ...

Pergamon-Elsevier Science Ltd2014

Functionalized graphene grown by oxidative dehydrogenation chemistry

László Forró, Daniel Oberli, Arnaud Magrez, Arnaud Walter, Jacim Jacimovic, Massimo Spina, Endre Horvath, Laurent Syavoch Bernard

We report on a highly efficient growth of graphene using dehydrogenation of acetylene by an oxidative reaction with carbon dioxide. In few seconds, large-area of copper foil used as catalyst of the reaction is fully covered with graphene. The yield of the ...

Pergamon-Elsevier Science Ltd2014