Implication of Amorphous-like Raman Spectra of Gas-Evaporated Si and Ge Microcrystals

Si and Ge particles prepared by the gas evaporation technique, if sufficiently small show completely amorphouslike Raman spectra. However, high resolution electron micrographs of these particles clearly show lattice fringes, proving that they are crystalline. The amorphous-like Raman signal seems to come from the surface layers of the microcrystals.