Raman scattering technique in characterisation of glasses containing silicon nanoparticles for optoelectronics

The Raman scattering on acoustical phonons from silicon quantum dots in glass matrix were investigated. Two peaks that correspond symmetric and quadrupolar modes of spherical vibrations were found and compared with the model calculation for in- and off-resonance scattering conditions. In both models the homogeneous broadening due to interaction with matrix and inhomogeneous broadening due to particle size distribution as well as the frequency red shift were found. The comparison of the model fit on the Raman spectra with the size distributions measured by HRTEM showed that resonant scattering mechanism with the light to vibration coupling coefficient strongly dependent on the particles size is responsible for the observed Raman spectra.