The scientific activities of the Nanostructures and X-ray Radiation (NRX) team focus on the study of nanostructures using laboratory and synchrotron X-rays. They contribute to the scientific and technological objectives of the CEA and the French community in the development of materials, components, technologies, and analysis methods. This requires the implementation of very specific equipment and scientific expertise to carry out high-level academic or applied experiments.
The NRX manages and participates in the hosting of the Irig X-ray characterization platforms and the French beamlines of the ESRF located in Grenoble. It conducts its research there, as well as at other synchrotrons around the world.
The team's instrumentation includes powder, single crystal, and medium/high resolution thin film diffractometers. We also use a small angle instrument located at the PFNC (Grenoble Nanocaracterization Platform). We provide support for measurements as well as data processing and analysis.
At the ESRF site, the CNRS and the CEA have jointly built and operate the French CRG beamlines (F-CRG) in order to offer French researchers world-class X-ray beams, cutting-edge techniques, and powerful analysis tools. This allows us to optimize human and financial resources, as well as our positioning in relation to other ESRF and Soleil beamlines in France. This coordination leads to a high degree of complementarity between instruments and scientific themes. Thus, we mainly develop experiments using the high energies of X-rays provided by the ESRF, i.e., beyond what is accessible at the Soleil synchrotron.
The NRX uses three instruments on the French
CRG BM32-IF beamline at the ESRF (4-circle goniometer, µLaue, ultra-high vacuum surface diffraction). It participates in their construction,
development, and user support.
Training all our users on all laboratory instruments or at the ESRF is one of the laboratory's important missions.
• Physics of SOI (silicon on insulator) materials. We focus on understanding the physics underlying the technological processes involved in producing these materials, namely bonding, ion implantation, and fracture. To do this, we use hard X-ray diffraction/scattering techniques and laboratory experiments. These are carried out at the joint CEA-SOITEC laboratory.
• Electronic and optoelectronic materials: Deformation and composition. We participate in the development of advanced IV-IV (Si, Ge, Sn) and III-V nitride (Ga, Al, In, N) semiconductor materials and devices using cutting-edge techniques associated with nano-beams: e.g. ptychography, coherent or full-field diffraction, X-ray excitation, fluorescence, and µ-Laue diffraction. Particular emphasis is placed on operando measurements.
• In situ and operando study of the structural evolution of catalytic nanoparticles in their environment and during the reaction using coherent diffraction imaging under Bragg conditions.
• Growth of 1D and 2D materials under X-ray beams: structure and kinetics. In situ studies of X-ray diffraction/scattering of nanomaterials during growth using physical or chemical evaporation processes. Studies have focused on the growth of graphene on Ir, the organization of metal particles, Si-Ge nanowires and, more recently, the growth of various 2D materials based on Te and S.
• Crystallographic and kinetic phases of materials for batteries and sol-gel with CEA-Irig and Liten to study the fundamental mechanisms involved in their structural evolution operando.
• II-VI materials for high-performance IR detectors. Structural and chemical studies of semiconductor heterostructures in devices using µLaue and EXAFS techniques.
• Simulation of vicinal surface models. Quantification of the relationships between surface energies and stresses using empirical potentials in silicon and metals.
Industrial partners : SOITEC, LYNREDAcademic partners : ANR Française ; Commission Européenne ; ESRF ; CEA : Irig, Leti, Liten ; CNRS : Institut Néel, C2N ; Université de Leiden (Pays-Bas) ; NCSR Democritos (Grèce) ; MPIE Düsseldorf (Allemagne) ; Université technique de Lisbonne (Portugal).