Inelastic light scattering: a multiscale characterization approach to vibrational, structural and thermo-mechanical properties of nanostructured materials

Inelastic light scattering is a powerful technique for the characterization of nanostructured materials, at different length scales. Raman scattering is a well established tool for materials characterization (structure, bonding and composition), through the measurement of vibrational properties. Due to phonon confinement, the Raman spectra of nanoparticles and nanostructured materials are substantially different from the spectra of the corresponding bulk, and provide useful information relative to the size and the dynamical behavior of the building blocks. In situ measurements permit the investigation of phenomena such as cluster deposition, film growth, thermal and chemical stability of nanostructures. Brillouin spectroscopy measures acoustic phonons and elastic properties of thin films and bulk materials at a mesocopic scale (hundreds of nanometers). The observation of acoustic damping and localization in nanostructured materials gives access to information such as interaction between nanoscale constituents, phase transitions, self-similar properties and meso-structure dynamical behavior. We provide a wide range of examples: characterization of the elastic properties of cluster-assembled films and ultrathin protective layers; in situ Raman spectroscopy of metastable linear carbon aggregates (carbynes) produced by cluster beams; measurement of acoustic modes in carbon nanotubes; detection of surface melting of metallic nanoparticles, by detection of confined vibrational modes. # 2003 Elsevier B.V. All rights reserved.