Advanced Raman Characterization Techniques

This outline of the principal characterization techniques for nanocomposite materials is far from being complete. Advances in Raman spectroscopy, energy dispersive spectroscopy, infrared spectroscopy, and many other techniques are of considerable importance as well. In fact, the success that nanos-tructured materials are having in the last few years is strictly related to the advanced characterization techniques that are available today. 

Rapid advances in semiconductor techrwlogy, including thin film formation by deposition, interface preparation or microstructuring, demand characterization techniques that provide understanding of the fundamental processes involved, including information on structural order—disorder and spatial inhomogeneity. Raman spectroscopy is used both in process control and quality assessment [34]. Typical examples of semiconductor applications are composition determination, analysis of crystal structure, surface and interface analysis, phase determination, doping, point defects, temperature influence and mechanical stress. 

Raman Scattaring. Althongh the Raman effect was first reported in 1928 (18,19), its utility as a characterization tool was not realized until the advent of lasers in the early 1960s (20). With the recent advances in lasers, detection systems, and spectrometer design, a tremendons potential exists for use of the Raman technique as a characterization technique. Since it is a scattering techniqne, samples such as powder, film, solid, filament, or solntion can all be studied... 

Vibrational spectroscopy is an important tool for the characterization of various chemical species. Valuable information regarding molecular structures as well as intra- and intermolecular forces can be extracted from vibrational spectral data. Recent advances, such as the introduction of laser sources to Raman spectroscopy, the commercial availability of Fourier transform infrared spectrometers, and the continuing development and application of the matrix-isolation technique to a variety of chemical systems, have greatly enhanced the utility of vibrational spectroscopy to chemists. 

We ve tried to include all substantial developments and advances in this new edition. Significant developments in biomedical applications, microelectromechani-cal systems, and electronic textiles have been included, as has synthesis of nano-structured CEPs. New methods for characterizing CEPs, such as electrochemical Raman and electron spin resonance spectroscopy, have also been described. Significant progress is also detailed in techniques for processing CEPs and the fabrication of devices. 

In light of recent advances in solid state Hg NMR, Raman, IR, EXAFS, and electronic spectrocopies summarized here, Hg(II) complexes can no longer be considered as spectroscopically silent. A formidable barrier to establishing reliable spectroscopic correlations with the coordination environment still exists because of the small number of well characterized small molecule complexes. Solution Hg NMR, vibrational, and electronic spectroscopies can distinguish complexes with a coordination number of 2 from those with CN = 3 or 4. None of these techniques can readily distinguish between three and four coordination however. Recent advances in solid-state Hg NMR spectroscopy unequivocally demonstrate that Hg-SR complexes with a primary coordination number of three or four can be readily distinguished. 

Raman spectroscopy has recently gained popularity for advanced chemical analysis of surfaces. In nanoscience, Raman spectroscopy is used to characterize surface properties of materials, measure temperature, and determine crystallinity. Raman spectroscopy is a spectroscopic technique used in material science to study vibrational and rotational frequencies in a system. The technique measures shifts in inelastic scattering, or Raman scattering, of light from a visible, near infrared or near ultraviolet light source and the shift in energy provides information about the material s surface characteristics. The Raman signal unit is a measurement of the ratio between the Stokes (down-shifted) intensity and anti-Stokes (up-shifted) intensity peaks. 

The development of novel silicone material requires extensive characterization in order to estabhsh the structure and property relationship. The spectroscopic techniques such as FTIR, Raman, XPS, NMR, and SIMS could complement each other md provide vcduable insight of materials chemistry. The hcud to find spectroscopic assignments of silicones have been detailed in this chapter. This chapter briefly summcuized the utihzation of spectroscopic techniques on sihcone coatings, biomaterials and other advanced silicone materials. The emergence of new 2D correlation studies being conducted in material science have been deemed to enhance the screening capability of these spectroscopic techniques. 

---