Raman and x-ray scattering from ultrafine semiconductor particles

Publisher Website
Google Scholar
Abstract
We prepared ultrafine germanium particles by gas‐evaporation techniques. The particle composition was studied by Raman and x‐ray scattering. We take an analytical model to explain the Raman profile: the particle is composed of a single‐crystalline core and a coating amorphous shell. In this single‐crystalline part, the phonon mode is completely localized, and as a result the red shift and the broadening of the Raman signal are induced. We introduce a localization factor to describe the size effect. According to this model we determined the mean diameter of a crystalline particle. The result is compared with that from x‐ray diffraction. Our results indicate that the coating amorphous shell thickness is nearly constant, although the crystalline particle size varies by the evaporation‐gas pressure. Furthermore, we found that the Raman profile changes by the wavelength of the exciting laser.