Description du sujet de thèse

Nano-materials are a vast family of emerging materials for microelectronics and photonics which have a wide variety of electronic, dielectric, phononic, magnetic properties... Their shape is structured at the nanometric scale: either in the three directions of space (fullerenes, nanocrystals, etc.), either in two directions in space (so-called “1D” materials such as carbon or boron nitride nanotubes, etc.), or in one direction in space (“2D” materials such as graphene, boron nitride, etc.). These materials have in common the fact that it is possible to grow or transfer them on a very wide variety of substrates. It is also possible to arrange them in order to obtain particular properties, which multiplies the number of degrees of freedom available for the production of new devices. The use of substrates made of widespread materials and whose manufacture is energy efficient makes it possible to envisage electronics at lower cost and more respectful of the available planetary resources. However, it is necessary to develop growth and/or transfer techniques for these nano-materials, it is also necessary to characterize the properties of these nano-materials at nanometric scales in order to optimize their manufacturing processes. Local probe imaging techniques are well suited for this type of characterization, in particular scanning near-field optical microscopy (SNOM). It has proven to be very powerful for the characterization of nano-materials: nanocrystals, nanowires, 2D materials. It makes it possible to simultaneously acquire the topography of a sample and the electromagnetic behavior of the material located under the measurement probe. Thanks to its radius of curvature, it is possible to obtain spatial resolutions of a few tens of nanometers compatible with current technologies. The thesis aims to study different nano-materials thanks to a SNOM operating in the mid-infrared and in the terahertz range, a particularly interesting frequency range to study the collective oscillations of electrons (plasmons) and the vibrations of the crystalline structures (phonons) of nano-materials. These studies will be supplemented by other complementary characterizations such as Raman spectroscopy, terahertz spectroscopy in the time domain, photoluminescence, and FTIR spectroscopy at SOLEIL synchrotron. Finally, the applications of these nano-materials for the production of devices at terahertz frequencies will be considered.

Contexte de travail

The candidate will be located at the IEMN, Avenue Poincaré, Villeneuve d'Ascq, one of the laboratories in the network of major Renatech and RF-NET power plants in France. They will have full access to the various technical solutions required for the project's implementation. The IEMN brings together, within a single structure, the bulk of regional research in a vast scientific field ranging from materials physics, nanostructures, nanoelectronics, microelectronics, microwaves, microsystems, telecommunications systems, and instrumentation. The thesis will be conducted within the laboratory's Terahertz Photonics Team and the Optical and Photonics Hyperfrequency Characterization Center. This center brings together the experimental resources necessary for the thesis. The position is located in a sector covered by the Protection of Scientific and Technical Potential (PPST), and therefore, in accordance with regulations, requires that your arrival be authorized by the competent MESR authority.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

- Use of lasers