Characterisation

The characterization offer will provide all the tools necessary to characterize the fabricated samples from the intimate atomic structure to the macroscopic physical properties. The available tools range from table top experiments to large scale facilities. The offer is divided into three installations. The first one is dedicated to unveil the atomic structure and the morphology, including far field and near field microscopy, structural characterizations through electrons, X-rays and neutrons. The second installation aims to give access to the electronic band structure and the chemical states, it includes photo emission and spectroscopy in a wide wavelength range from X-ray to far infrared. Finally the third installation concerns the macroscopic characterizations leading to the electrical and magnetic properties ranging from standard transport measurements to determine the electron density and mobility to SQUID and neutron scattering for the magnetization of the sample.

Structural & Morphology Installation 4

Confocal microscopy

Confocal microscopy is an optical imaging technique that creates a virtual plane or slice, many micrometers deep within the analyzed sample. Compared to conventional microscopy, it provides fine detailed images of higher quality and with more contrast. In addition, virtual 3-D images of the analyzed microstructure can be obtained by this technique when multiple sections are combined and reconstructed by means of a dedicated computer and software.

Laser scanning confocal microscopy

This technique has the mission of enabling researchers to visualise and to monitor cellular events in real time and in vivo down to the molecular level, enabling prolonged observations that are not possible with classic confocal microscopes and allowing unparalleled detail in soft matter imaging.

AFM Atomic Force Microscopy

AFM is a surface sensitive technique permitting to obtain a microscopic image of the topography of a material surface. Typical lateral image sizes are within a range of only a few Nanometers to several 10 Micrometers, whereas height changes of less than a Nanometer may be resolved. Additional surface properties may be obtained for each point of the scan such as friction force by lateral force imaging and magnetization properties by magnetic force imaging.

STM Scanning Tunneling Microscopy

STM allows imaging conductive surfaces at the atomic scale. It is possible to characterize the distribution of surface terraces and steps, as well as to determine the atomic arrangement of (ordered) surface (over)structures.

SEM Scanning Electron Microscopy

In SEM a beam is scanned over a sample surface while a signal from secondary or back-scattered electrons is recorded. SEM is used to image an area of the sample with nanometric resolution, and also to measure its composition, crystallographic phase distribution and local texture.

TEM Transmission Electron Microscopy
In TEM/Scanning TEM (STEM) high energy electrons incident on ultra-thin samples, allow imaging, diffraction, electron energy loss spectroscopy and chemical analysis of solid materials with a spatial resolution on the order of 1-2 Å. Samples must have a thickness of a few tens of nanometres and are prepared in sample preparation laboratory.
SIMS Secondary Ion Mass Spectrometry

SIMS uses a focused, energetic primary ion beam to bombard the surface of the sample of interest. Atoms are sputtered, ionized and accelerated towards a mass spectrometer. SIMS can provide surface mass spectra, images with lateral resolution in the 0.1 to 10 µm range and depth profiles with depth resolution in the 1 to 10 nm range. SIMS can be quantitative when reference samples are used and can achieve ppm or even ppb sensitivity.

MEIS Medium Energy Ion Scattering

MEIS measures the backscattering of a primary monoenergetic ion beam (typically 100 keV H+ or He+) with target nuclei of the sample. The energy and angle of the back-scattered particles enable information on composition and structure (defects and strain) to be deduced in the near surface region (sub-nm depth resolution can be achieved in the near surface region, with picometer accuracy in measuring atomic displacements).

XRM X-Ray Microscopy

Scanning Transmission X-Ray Microscopy (STXM) is a non-invasive x-ray microscopy technique that enables the acquisition of images with elemental, chemical, and magnetic sensitivity. Typical STXM images exhibit a spatial resolution on the order of 10-20 nm, depending on the zone plate employed to focus the x-rays, and a typical lateral image size on the range of 1-100 µm. This technique requires x-ray transparent samples (typically fabricated on thin Si3N4 membranes or supported by TEM grids).

XRT X-Ray Tomography

X-ray Computed Tomography (CT) is an indirect (a specialized algorithm is used to reconstruct the distribution of X-ray attenuation) nondestructive technique for visualizing interior features within solid objects, and for obtaining digital information on their 3-D geometries and properties. Scanning x-ray tomography can also be performed using an x-ray beam focused on the sample; in that case the resolution of the direct image is given by the beam size.

SAXS Small Angle X-ray Scattering

SAXS is a non-destructive and versatile method to study the nanoscale structure of any type of material ranging from new nanocomposites to biological macromolecules. Parameters as averaged particle sizes, shapes and distributions, the materials' porosity and degree of crystallinity as well as electron density maps with nanometer precision can be obtained. Materials can be solid, liquid or even exhibit gaseous-like properties as aerosols.

XRD X-Ray Diffraction

XRD provides non-destructive information on the structural order of a material. At large scattering angles XRD permits to identify different crystal phases and to quantify lattice distances and crystalline volume fractions. At low angles of incidence the surface roughness of a single crystal and the thickness of a deposition layer can be obtained. At an angle of incidence below the critical angle XRD is highly surface sensitive.

Neutron Imaging

Neutron imaging allows performing radiography and tomography with fields of view ranging from 20 to 100mm. In the case of large objects need to be measured, radiography can be performed with a field of view of 200x400mm². Several types of sample environment can be provided to the users: furnace (up to 200°C), humidity chamber. The large table for the sample holder allows setting up any sample environment provided by the users.

Neutron Diffraction

Neutron diffractometers are well adapted to take measurements on powders, poly-crystals, liquids and amorphous materials. These experiments enable to determine: 1) in crystals, the symmetry of the cell and the average position and space occupied by each atom, 2) in disordered systems, pair correlation functions. Thanks to their specific properties, the neutrons can “see” light atoms easily, hydrogen in particular. The choice of the instrument is determined by the general size of the crystal cell parameter and the required resolution.

Neutron Reflectivity

Neutron reflectivity is dedicated to the study of interfaces. The reflected intensity at grazing angle of a non polarized white neutron beam is measured as a function of wavelength. The variation of reflectivity is linked to the concentration profile perpendicular to the interface. The thickness, composition and roughness of each layer of the profile is determined within the range from 2 to 500nm for thickness and 1 to 20nm for roughness. All type of interfaces might be studied, including air/liquid interfaces.

SANS Small Angle Neutron Scattering
SANS produced by nano-objects (polymers, micelles, vesicles, proteins, precipitates, critical fluctuations, vortex ….) enables to measure the size of the scattering objects between 0.1 et 100 nm. Built to characterise large size objects, SANS spectrometers measure the quantity of neutrons scattered «near the forward direction», that is to say resulting from a process characterised by very small transfers of momentum.
Atom Probe Tomography

A voltage and/or a laser pulse is used to field evaporate atoms from the end of a specimen in the form of a sharp tip. By measuring the time-of-flight and the position of the evaporated atoms on a position sensitive detector a 3-D reconstruction of the position and chemical nature of detected atoms is possible. This technique has sub-nm resolution (around 0.1-0.3nm resolution in depth and 0.3-0.5nm laterally) and detection efficiencies as good as 80%.

Cathodoluminescence

The cathodoluminescence integrates a scanning electron microscope (SEM) and a light microscope into one tool allowing SEM images and electron beam induced-luminescence images to be acquired at the same time. The analysis of the features in the luminescence spectra allows the characterization of the material properties (charge carrier recombination, electronic transition) and the detection of defects or impurities.

Fluorescence Microscopy Hybrid tomographic and Light Sheet Fluorescence Microscopy
The hybrid Optical Projection Tomography and Selective Plane Illumination Microscopy (OPT-SPIM) is used to produce optical sectioning of molecular structures (soft materials, biological tissue, etc) with submicron resolution.
Optical Thin Film Metrology

Thin film reflectometry is a fast and easy technique used to measure the thickness of thin transparent and semi-transparent films on transparent and absorbing substrates. It covers a broad thickness range and can be applied to a high variety of material systems due to the large and extensible material library.

Electronic & Chemical Installation 5

XPS X-ray Photoelectron Spectroscopy

XPS is a surface spectroscopic technique for quantitative measurements of the elemental composition or stoichiometry and the chemical state of the present elements, like their oxidation state and chemical bonds. Due to the limited free path-length of the excited photoelectrons within the material, XPS is highly surface sensitive, giving chemical and binding energy information from the a narrow region close to the surface.

XAS X-ray Absorption Spectroscopy

XAS is sensitive to the local bonding environment of the atom absorbing the X-rays, providing information on oxidation states, local orbital symmetry, molecular orientation and chemically selective density of states. It is widely used in molecular and condensed matter physics, material science, engineering, chemistry, earth science and biology.

XMCD/XMLD X-ray Magnetic Circular/Linear Dichroism

When X-ray absorption is measured with circularly/linearly polarized x-rays, spin and angular momenta contributing to the net magnetization / orientation of the magnetization axis, can be determined in ferromagnetic / antiferromagnetic systems, respectively. Dichroic effects arise by the difference between spectra measured with different helicity (left and right circular polarization) / polarization orientation of the X-ray photons.

XPEEM X-ray PhotoEmission Electron Microscopy
It is a parallel (full-field), surface-sensitive imaging method using photo-excited electrons, and is therefore related to the photoemission process. Depending on whether secondary electrons or true core-level electrons (both element- and bonding state-specific) are used, the image can be characteristic either of the work function anisotropy, or of heterogeneities in elemental distribution and chemical changes at the surface of interest.
IXS Inelastic X-ray Scattering

Inelastic X-ray scattering (IXS) permits to analyse several aspects of the dynamics of materials. The techniques involved include Compton scattering, X-ray Raman scattering, and resonant inelastic scattering. In this way electron momentum densities and atomic bonding can be probed and also magnetic excitations or electronic localised or collective states and electronic band-structures.

ARPES Angle Resolved Photoelectron Spectroscopy

ARPES allows to measure directly the electronic band structure of crystalline solids. Electrons are detected retrieving information about initial state energy, momentum and spin.

XPD/RESPES/RESPED Resonant Photoemission Spectroscopy/Diffraction

Valence photoemission performed in resonance with core photo-ionization allows to study charge transfers between adsorbate species and the substrate surface and their time scale. If polarisation and emission angles are taken into account, specific atomic sites/bonds of complex molecules are probed. The technique is useful in applications where electron-hole creation and transport phenomena are involved.

IPES Inverse PhotoEmission Spectroscopy
IPES probes the empty density of states above the Fermi level of conduction/valence band in condensed matter. The energy of the impinging electron is varied while photons are detected at fixed energy; in this way the spectrum of the density of unoccupied states, is obtained. IPES technique is complementary to Photoemission (PES) and combined PES-IPES data provide information on the surface electronic transport gap of sample.
AES-SAM Scanning Auger Microscopy

Auger Electron Spectroscopy (AES) and SAM are electron beam techniques allowing the analysis of the surface elemental composition of materials. By pointing or scanning the electron beam, localized information or spatial elemental distributions can be obtained. Auger depth profiling allows measuring elemental concentration profiles. In-depth information can also be obtained by analysing a cross-sectional sample.

IR spectroscopy UHV reflection-absorption IR spectroscopy
An infrared spectrum is commonly obtained by passing infrared radiation through a sample and determining what fraction of the incident radiation is absorbed at a particular energy. The peak position in the absorption spectrum corresponds to the frequency of a vibration in the sample molecule.
FTIR Fourier Transform Infra Red
IR spectroscopy is based on the absorption of infrared radiation by matter. This leads to energetic transitions in the vibrational state of concrete chemical bonds. Since the frequencies that are absorbed by the molecules are characteristic of their structure, this technique is a powerful tool for qualitative molecular analysis, although it can also be used quantitatively.
Raman spectroscopy

Raman spectroscopy investigates the vibrational properties of a sample and provides chemical as well as structural information (for example, chemical composition, molecular arrangement or the crystalline structure). Raman spectroscopy does not require any specific sample preparation, size or condition and may be combined with micron spatial resolution when operated using a confocal microscope, and nanometric resolution when operated in TERS or SNOM configuration.

Optical spectroscopy

UV/Vis/NIR spectroscopy is the measurement of the attenuation of a beam of light after it passes through a sample or after reflection from a sample surface. It is useful to characterize the absorption, transmission, and reflectivity of a variety of technologically important materials, such as pigments, coatings, windows, and filters.

PL PhotoLuminescence
PL is a non-contact, non-destructive method of probing the electronic structure of materials, often used in the context of semiconductor devices to determine the bandgap energy, the composition of heterostructures, the impurity levels, the crystal quality, and to investigate recombination mechanisms.
Microluminescence
Luminescence is any process in which light is emitted from a sample as a consequence of an excitation obtained through electrical polarization, electronic bombardment, optical illumination or magnetic excitation. The spectrum (color) of the emitted light provides important information on the electronic structure of the material. Introducing a microscope in the experimental system, microluminescence provides information on the spatial distribution of the electronic structure into the material.
EPR Electron Paramagnetic Resonance
EPR technique allows the detection and study of transient and stable paramagnetic species such as free radicals, over a very wide range of temperatures.
Ellipsometry
Ellipsometry is a contact-free, nondestructive method for characterization of the dielectric and optical properties (refractive index, absorption and thickness) of layered nanostructures in the size range of < 1 nm to several μm.
Pump-probe
The pump-probe spectroscopy infrastructure provides in-situ probes of the excited state of the matter, i.e. in the time/frequency domain at the fs-ps scales.
Optical Manipulation
Optical tweezers use radiation pressure of a laser focused by an optical microscope to handle micro-objects and to apply pN forces. It can be used in a variety of fields and joined with optical spectro-microscopies, mainly in soft matter. At present optical manipulation stations including multiple trapping, manipulation, force measurements, laser microsurgery, Raman spectroscopy, phase contrast imaging, TIRF and FRET are operative.
In-operando spectroscopy

Soft X-rays XAS operating at Ambient Pressure allows for in-operando (under working condition sample environment) spectroscopic investigation of surfaces and their catalytical properties. This opens interesting access to L and M-edges of most of the transition metals and K-edges of light elements (C, O and N). The high surface sensitivity is achieved by the total electron yield detection.

Magnetic, Optical & Electric Installation 6

MOKE Magneto-Optic Kerr Effect
By MOKE the magnetic properties (e.g. coercivity, squareness ratio) of single micro-structures can be evaluated: no quantitative measure of the magnetization is provided, but from the shape of the hysteresis loop, both static and dynamic magnetization reversal processes can be investigated in detail.
Magnetometry
The facility provides an automated MagLab-EXA multi-measurement system for nanomaterials characterization. A set of analytical probes (AC/DC magnetometry, magneto-transport, Hall effect etc) is available to indentify technologically useful quantum mechanical phenomena to design materials (e.g. semiconductors, metals, magnetic oxides) with optimal device operational capabilities, such as in magnetic storage technology, spin electronics etc.
SQUID Superconducting Quantum Interference Device
SQUID offers high resolving power in deciphering static and dynamic phenomena in low-moment, dilute magnetic systems. Invaluable insights on the physical-chemical response of magnetic nanomaterials are attained by measuring moment versus applied magnetic field or moment versus temperature. It also allows precise determination of the Curie, Néel or blocking temperatures of ferromagnetic, antiferromagnetic or superparamagnetic nanoparticles.
Magneto-transport
The facility allows magneto-transport characterizations of semiconductor and metallic samples at temperatures down to liquid helium and fields up to 7T. Density and mobility of carriers can be measured through Hall effect, as well as quantum transport phenomena in 2D systems at low T. Carrier populations can be tuned by bias voltages and external illumination.
Magnetic/ferroelectric/dielectric char.

The facility provides modular experimental stations to study the evolution of electric and magnetic dipole orders, as well as their degree of coupling, which is an identifying feature of novel magneto-electric systems. The users may assess technologically appealing materials’ features for designing multifunctional devices, such as magneto-electric sensors or high-capacity four-state logic memories.

MNR Magnetic Neutron Reflectivity
With MNR is possible to investigate thin magnetic layered structures down to thicknesses between 3–300 Å and lateral structures from nm to µm. The reflection of polarised neutrons allows to determine the density and the modulus and the direction of the magnetisation vector of buried layers. Magnetic roughness, magnetic domains, lateral structures, density profiles, structures of solid polymer layers, etc. are investigated.
DNS Diffuse Neutron Scattering
DNS with single-crystal time-of-flight spectroscopy is ideal for the studies of complex spin correlations, such as in highly frustrated magnets and strongly correlated electrons via neutron polarization analysis. DNS also represents a powerful instrument for the soft condensed matter community for the separation of nuclear coherent scattering from often dominating spin incoherent scattering background in a wide-angle diffraction experiment.
Magnetic SANS Magnetic Small Angle Neutron Scattering
SANS is used for the analysis of structures between 1 and about 100 nm, which can not be characterised by microscopies or when samples are turbid due to multiple light scattering. SANS gives access to the structural investigation and the samples do not need to be diluted. In KWS-1 beamline magnetic samples are studied with the full polarisation analysis. In KWS-2 the contrast variation method allows for highlighting of particular components.