Seminar Prof. Ludger WIRTZ

Optical and vibrational properties of MoS2
Ludger WIRTZ
Physics and Materials Science research unit, University of Luxembourg
26/11/2013 à 11h00 – Salle du Conseil – IEMN

Following the hype on graphene, other layered materials are recently achieving a lot of attention.
One of them is molybdenum disulfide. Contrary to graphene, MoS2 has a band-gap of about 2 eV
and might thus be a suitable candidate for electronics and optics applications. I will give an
overview over the properties of the material and summarize the ongoing debate on the mobility of
the material. I will also present our own recent work on the phonon dispersion of of bulk and fewlayer
MoS2, where the origin of the anomalous Davydov splitting is still not ultimately clarified.
Furthermore, I will discuss the influence of excitonic effects and spin-orbit splitting on the optical
properties of MoS2.

Seminar Daniel MANDLER

« Chemistry and Electrochemistry in Two Dimensions: from Langmuir Blodgett Films to Monolayers and Polymeric Films »
Prof. Daniel MANDLER
Daniel.mandler@mail.huji.ac.il
Institut of Chemistry, The Hebrew University of Jerusalem, Israel
27/11/2013 à 14h00 – Salle du Conseil de l’IEMN

 

Electrochemistry deals with charge transfer across interfaces. As is well known, the structure of the interface affects very much charge transfer and therefore controlling and characterization the interface on a molecular level is of utmost importance.
The lecture will focus on different approaches for controlling the interface and its implications and applications in electrochemistry. These will include structuring the interface using Langmuir and Langmuir-Blodgett films, applying self-assembled monolayers and if time permits manipulating thin polymeric films. Different systems and applications will be presented; films at the water-air interface based on individual molecules, polymers and nano-objects. Applications of functionalized self-assembled monolayers as a means of selectively interacting with metal ions and organization of asymmetric nano-objects for future photocatalysis, will be described. Various characterization methods will also be discussed such as horizontal touching voltammetry and scanning electrochemical microscopy.



Séminaire du Groupe Physique

Characterization of Phosphorus Doped Silicon Nanocrystals Embedded in SiO2

October 17, 2013 – at 2pm – IEMN, LCI – Salle du Conseil

Presenter
Sebastian Gutsch – University of Freiburg
sebastian.gutsch@imtek.uni-freiburg.de

Abstract
Phosphorus (P) doped silicon nanocrystals (Si NCs)   are prepared by deposition and annealing of P doped silicon-rich oxide /   silicon oxide (SiO2) multilayers. The chemical environment of P is   determined from X-ray photoelectron and X-ray absorption near edge   spectroscopy. It is found that P is incorporated into the Si NCs down to   diameters of about 2.5 nm. However, the results suggest that essentially no   free electrons are generated in this doping process. Using atom probe   tomography, it is further found that large amounts of the dopants segregate   at the Si NC / SiO2 interface. In addition, photoluminescence   spectroscopy and electrical characterization of the multilayers indicate that   the majority of incorporated P atoms have only a small impact on the optical   and electronic properties. It is shown that less than 1% of the doped P atoms   occupy a substituitional site and that the donor ionization energy   significantly exceeds kT at room temperature.

Secondes Journées Franco libanaises (brèves)

Secondes journées franco libanaises
Trois universités régionales (Lille 1, UVHC et ULCO) en partenariat avec l’Université Libanaise et tous les partenaires de l’ARCUS E2D2 organisent du 22 au 25 octobre 2013 « Les Secondes Journées Franco-Libanaises ».
>> En savoir plus

Secondes journées Franco-Libanaises JFL2 : Avancées de la Recherche et de ses Applications

2nde Journees Franco Libanaises Du 22 au 25 octobre 2013 – ULCO Côte d’Opale

Dans le but de créer un réseau de collaborations regroupant les principales disciplines scientifiques au sein d’un groupement de recherche international, trois universités régionales (Lille 1, UVHC et ULCO) en partenariat avec l’Université Libanaise et tous les partenaires de l’ARCUS E2D2 organisent du 22 au 25 octobre 2013 « Les Secondes Journées Franco-Libanaises ».

L’un des objectifs principaux est de renforcer les actions en cours, principalement celles qui ont conduit ou peuvent conduire à des thèses en cotutelle. Développer des formations sous forme de masters en double diplôme et initier l’émergence d’équipes de recherche regroupant les principaux partenaires au sein de groupes de recherche internationaux. Avec la participation des laboratoires de recherche : IEMN DOAE, CALHISTE, LAMAV, LMCPA.

Cinq sessions sont prévues, illustrant chacune les grandes thématiques des différents laboratoires libanais, français et autres partenaires (Maroc et Palestine). Dans chaque session, des conférences sélectionnées par le comité scientifique seront données par des représentants des laboratoires participants et des invités. A l’issue de chaque session, une séance de posters est prévue afin de  donner l’occasion au plus grand nombre de participants d’exposer leurs travaux.

Des visites des Maisons de Recherche dans les différents sites de l’ULCO (Dunkerque – Calais – Boulogne sur Mer) seront également proposées.

  • Session 1 : Aménagement et Développement Durable
  • Session 2 : Infrastructures et Systèmes Complexes
  • Session 3 : Expertise et Traitement en Environnement
  • Session 4 : Optique, Lasers, Interface Physique–Biologie Session 5 : Table Ronde ARCUS E2D2

Plaquette de présentation

Contacts Pr Edmond ABI-AAD edmond.abiaad@univ-littoral.fr

Pr Antonio KHOURY akhoury@ul.edu.lb

Inscriptions : www.jflpi.fr

Zero-dimensional transistor harvests bubble energy wasted during water electrolysis

A zero-dimensional transistor is placed in contact with a water droplet containing NaCl ions. A current between the anode and cathode generates hydrogen and chlorine bubbles, which the transistor can detect and transform into electric pulses. N. Clément et al. © American Chemical Society

 

When hydrogen is produced from water during electrolysis, some energy is lost at each bubble emission. In a new study, researchers from the Institut for Electronics Microelectronics and Nanotechnology (CNRS/Univ. of Lille),  NTT, Tokyo and CEA Marcoules have demonstrated that 25-nm transistors — so small that they are considered zero-dimensional (0D) — can be used to transform this lost energy into electric pulses. Millions of these 0D transistors could be used to detect individual bubbles and generate electric pulses at an optimal efficiency, gathering part of the energy lost during electrolysis and making it available for other uses. In theory, 2 million 0D transistors could fit below the microbath, which results in an output pulse power of 500 µW and a pulse power efficiency of about 99%.

These results could have a variety of applications, such as lab-on-chip devices for hydrogen emission. Another potential application is in physiology, since the electric signal has a similar amplitude as that of the action potential in a neuron.

 

This paper was published in Nanoletters : Water Electrolysis and Energy Harvesting with Zero-Dimensional Ion-Sensitive Field-Effect Transistors. N. Clément, K. Nishiguchi, J.F. Dufrêche, D. Guérin, A.Fujiwara & D. Vuillaume. Nano Letters 13(8), 3903-3908 (2013), http://dx.doi.org/10.1021/nl4019879

Contact : N. Clément (nicolas.clement@iemn.univ-lille1.fr / 03 20 19 79 32)

Ferry Kienberger seminar

Scanning microwave microscopy: dopant profiling, spectroscopy, and modeling'
Ferry KIENBERGER

Agilent Research Lab (Linz, Austria)
24/10/2013 at 2.00 pm - IEMN Amphitheatre

Scanning microwave microscopy (SMM) is a recent development in nanoscale imaging technique that combines the lateral resolution of atomic force microscopy (AFM) with the high measurement precision of microwave analysis at GHz frequencies. It consists of an AFM interfaced with a vector network analyzer (VNA). SMM allows to measure complex materials properties for nanoelectronics, materials science, and life science applications with operating frequencies ranging between 1 MHz and 20 GHz. Here we present the basic working principles of SMM and advanced applications. In particular, calibrated capacitance and resistance measurements are shown with a noise level of 1 aF [1]. Calibrated dopant profiles are measured from 10E14 to 10E20 atoms/cm3 for nano-electronics characterization [2].
Pointwise C-V (capacitance-voltage) spectroscopy curves were acquired allowing for the characterization of oxide quality, interface traps, and memory effects of novel materials.
Additionally, a 2D mapping workflow was established to acquire roughly 20,000 C-V curves during one image [3]. Experimental investigations are complemented by finite element radiofrequency modelling using the 3D architecture of the probe and the sample, done with the Agilent software EMPro [4].

                  

Left panel: SMM setup. The AFM is interfaced with a Vector Network Analyzer measuring the electromagnetic properties of the sample. Right panel: Topography and dopant density (dC/dV) image of a semiconductor dopant sample with different dopant concentrations for quantitative and calibrated measurements.

References: [1] H. P. Huber et al, Calibrated nanoscale capacitance measurements using a scanning microwave microscope, Rev. Sci. Instrum. 81, 113701 (2010); [2] H. P. Huber et al, Calibrated nanoscale dopant profiling using a scanning microwave microscope, J. Appl. Phys. 111, 014301 (2012); [3] M. Moertelmaier et al, Continuous capacitance-voltage spectroscopy mapping for scanning microwave microscopy, Ultramicroscopy, Sept. 2013 online. [4] M. Kasper et al, Electromagnetic Simulations at the Nanoscale: EMPro Modeling and Comparison to SMM Experiments. Agilent AppNote Aug. 2013

Journée d’information Horizon 2020


 

Une journée d’information sur les appels en Technologies de l’Information et de la Communication (TIC) of programme H2020 de l’Union Européenne est organisée par Nord France Innovation Développement pour les acteurs du secteur des TIC en Nord, Pas-de-Calais.

Date : 3 octobre 2013 au Laboratoire Central de l’IEMN

Toutes les informations sur le site « J’innove en Nord – Pas de Calais »

The 2013 Bloch Prize recipient is Professor Bahram Djafari-Rouhani

2nd International Conference on Phononic Crystals/Metamaterials, Phonon Transport & Optomechanics
June 2-7, 2013 – Sharm El-Sheikh, Egypt

 


The Bloch Prize honors the eminent Swiss physicist wtho among many contributions to wave mechanics and theoretical physics formulated the underlying theory for electron wave propagation in periodic media. His theory, known as Bloch theory, laid the foundation for other theoretical developments ultimately leading to a formal classification of all crystals into metals, semiconductors and insulators. In recent years, Bloch theory r e-emerged as the basic underlying mathematical condition for formulating the band structure of modern periodic material such as phononic and photonic crystals.

 

The 2013 Bloch Prize recipient is Professor Bahram Djafari-Rouhani who is honored for his invaluable contributions to the areas of « superlattices, phononic crystals, phonon-photon interactions, plasmonics, and other related areas « starting with papers that date back to the early 1 980s and extending to the present time.

Lire l’article complet…

 

 

An IEMN researcher is awarded an ERC Starting Grant !

The project, named UPTEG « Unconventional Principles of ThermoElectric Generation », propose to test two unorthodox ideas to turn silicon into a thermoelectric material ! Indeed, thermal to electric energy conversion via Seebeck effect remains an inefficient process especially for low temperature gradients. In addition, conventional thermoelectric materials are polluting, rare and hardly compatible with microelectronics mainstream technologies…
However, silicon, which is a key material of microelectronics thanks to its electric propoerties, has an important Seebeck coefficient but suffers from a high thermal conductivity…

The project proposed by Jean-François Robillard, associate-professor at l’ISEN (Institut Supérieur d’Electronique et du Numérique) and researcher in the IEMN Microelectronics group rely on two approaches :
Phononic Engineering Converters : This approach envisions the periodic nanopatterning of silicon at the scale of the thermal phonon mean free path. This « artificial material » will exhibit a reduced thermal conductivity, down to 100 fold or 1000 fold as compared to bulk, and preserved electric properties.
Micro-Thermionic Converters : This approach is even more unorthodox and relies on building silicon electrode pairs separated by a vacuum gap in order to nearly supress thermal losses. The electrodes are functionalized thanks to low-workfunction material coatings (alcali oxydes) which enable electronic thermo-emission.
This research could lead to a better understanding of nanoscale heat transport and enable the fabrication of efficient micro-generators. Future developments envision mechanically flexible converters able to fit any surface.
The project relies on an ambitious program from simulation and material engineering to technology. It will benefit from the outstanding micro and nanofabrication facilities and caracterisation tools of the IEMN.
The European Research Council will provide funding up to 1.5 million Euros over the 5 years of the project which will lead to the recruitment of 5 PhD students and research associates, technological developments and dissemination activities toward general public as well as the scientific community.