Raman spectroscopy

Electronic & Chemical & Magnetic Characterization (Optical spectroscopy)

The Raman effect is observed when monochromatic light couples with molecular rotovibrational or crystal vibrational excitations in the sample under investigation. Some of the photons transfer a tiny amount of energy to the oscillating atoms, and the color of the scattered light is slightly redshifted. Although this effect was first observed by naked eye by sir C.V. Raman in 1928, is indeed very elusive. However, today, with the advent of highly monochromatic and high power laser sources and high resolution spectrometers, it gained a widespread diffusion for a large range of applications. Since the roto-vibrational information is specific to the chemical bonds and the symmetry of the molecules or of the crystal, the Raman spectrum provides a fingerprint by which the sample can be characterized with an incredible precision. 

The outstanding properties of Raman spectroscopy came to a price: usually Raman signal is disarmingly low. To circumvent this issue, strategies based on the plasmonic enhancement of the local electromagnetic field were proposed: with SERS (Surface Enhanced Raman Spectroscopy) amplification of the Raman signal up to 1014 times were shown; with TERS (Tip Enhanced Raman Scattering) spatial resolution down to 7nm was obtained. Choosing an excitation wavelength corresponding to an electric transition in the sample, Resonant Raman (SERRS) can be performed with a further enhancement in signal.

Operando Raman spectroscopy allows combining the powerful non-destructive chemical characterization capabilities of Raman spectroscopy with electrochemical evaluation. In this way, the evolution of the samples can be measured while applying electrochemical stimulus. A range of operando chambers is accessible to IREC, including electrochemical chambers (tight liquid chamber with reference electrodes) and high temperature stages.

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          provided at NFFA-Europe laboratories by:
CNR-IOM (TS)
Italy
CNR-IOM (PG)
Italy
CEA/LETI
France
C2N-CNRS
France
CSIC-CNM
Spain
CSIC-ICMAB
Spain
FORTH
Greece
JRC - ISPRA
Italy
UMIL
Italy
IREC
Spain
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          provided by:
EURONANOLAB
France
CEA/LETI
France
Micro-Raman
Chemical composition determination, crystalline structure characterisation, strain calculation, non-destructive fast measurements on liquids or solids
Multiple laser sources with optical power at the sample between 0.1 and 10 mW are focused on the sample using a confocal microscope
Available laser lines: 363, 488, 514 and 647 nm
Visible CCD detector: 220-800 nm
Spatial resolution between 0.5 and 2 µm depending on the chosen microscope objective Best spectral resolution 0.1cm-1
XY mapping stage range: 100 mm x 100 mm XY mapping stage resolution: 0.1 µm
From few mm2 to 12” diameter flat samples