Infrared and Raman Spectroscopies

The chapter is devoted to the Fourier transform infrared (FTIR) and Raman spectroscopy. The theory of both techniques has been briefly treated and the most widely used experimental apparatus have been described. The use of the FTIR and Raman spectroscopy for the characterization of silicon based films and the optimization of microcrystalline solar cell parameters, as examples of applications, have been reported. In particular, it has been shown that by means of FTIR it is possible to detect oxygen impurity in microcrystalline silicon, to individuate the device grade microcrystalline silicon for solar cells fabrication and to study the phase transition due to the thermal annealing of amorphous silicon carbon alloys (a-Si_1-xC_x:H) and a-Si_1-xC_x:H/SiC multilayers. Furthermore, it has been demonstrated that the Raman spectroscopy can be used for the optimization of J-V parameters of microcrystalline silicon solar cells, for the study of boron doping effect on the crystalline volume fraction in microcrystalline silicon carbon, for the investigation of crystallization process induced by thermal annealing in a-Si_1-xC_x:H/SiC multilayers, for determining the influence of the carbon alloying as well as the substrate on the crystalline volume fraction in nanostructured silicon carbon films and, finally, for the study on the medium range order in nanocrystalline silicon.

Keywords: Fourier transform infrared spectroscopy, raman scattering, vibrational modes, structural properties, silicon (hydrogenated) thin films, silicon carbon (hydrogenated) thin films, silicon nanocrystallites, solar cells parameters, thermal annealing, plasma enhanced chemical vapour deposition, average grain dimension, crystalline volume fraction, microstructure factor, oxygen impurities.