We perform structural (crystalline and morphological) and chemical analyses
required to qualify and validate the new materials and the elaboration
techniques developped in our laboratory. Resources used are, in particular,
X-ray diffraction, transmission electron microscopy, microanalysis and atomic
force microscopy. These activities are carried out into the
Elaboration and Physics of Epitaxial Structures
Several types of diffraction and reflectometry analysis are proposed at LPN with state-of-the-art X-Ray diffractometers. Crystalline structures, defaults, alloy composition, relatives crystalline orientations can be precisely studied in a non-destructive way for thin films and for assemblies of nanowires or quantum dots.
Auto-aligned multi-configurations diffractometer equipped with a 9kW rotating anode for powder diffraction, pole figures, reflectometry, high resolution diffraction, and grazing incidence diffraction (in-plane diffraction of crystallographic planes perpendicular to the surface.
Material characterization is required for producing optimally grown functional nanostructures. Transmission Electron Microscopy is a very powerful tool for investigating nanostructures at the atomic scale.
A transmission electron microscope corrected from spherical aberrations allows focusing a very intense electron current as high as 55pA in a beam of 1 Angstrom diameter, which is the size of a unique atomic column. Scattering electrons are collected for the image formation, while X rays produced when the electron beam impacts the structure are collected for a chemical cartography or a spectroscopic investigation of the composition at the atomic scale.
LPN has purchased a Jeol 2200FS Transmission Electron Microscope, equiped with a corrector of spherical aberrations on the STEM probe, and also with an "ultra-high resolution" objective lens. This combination of a TEM column with these analysis tools operating since end of 2008.
STEM image in high resolution annular dark field (HAADF) of a InAsP
quantum wire. Each white dot corresponds to an atomic column.
These wires are grown by Vapor Liquid Solid -VLS- technique in an MBE equipment (J.C. Harmand)
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