The effect of crystallite sizes L smaller than 100 nm on the integrated Raman cross section Σc of the transverse optical (TO) mode of fcc silicon was studied experimentally in fully nanocrystallized thin films. The Σc/Σa (amorphous) ratio of this mode is shown to be 1 up to L=30 Å, and to decay exponentially down to 0.1 at larger L. A systematic procedure taking into account both this effect and the experimental optical absorption coefficient αexp at the excitation wavelength is then proposed for the determination of the crystalline volume fraction in mixed phase (amorphous/nanocrystalline) silicon systems by Raman measurements.

The results of the structural, optical, and electrical characterization of ZnS, CdS, and Zn~_~CdxS films grown by the successive ionic layer adsorption and reaction process are presented. Polycrystalline cubic ZnS and hexagonal CdS films grown on glass and on indium-tin oxide covered glass have mean crystallite sizes Dl = 6.5 nm and Dll = 4 nm, and Dl = 30 nm and DII = 15 nm, respectively, perpendicular and parallel to the film. The pure cubic 3C phase is obtained from x = 0 up to x = 0.75 and the pure hexagonal 2H phase from x ~ 0.75 up to x = 1. Texturized heteroepitaxial films of hexagonal CdS have been grown on (111), (001), and (110) Ge, on (1 1 1), (001), an_d_(ll0) GaAs and on (1 1 1) InP substrates. Strongly texturized heteroepitaxial films of cubic ZnS have been grown on (1 1 1) InP and on (001) GaAs. Polycrystalline ZnS films consist of densely packed microcrystalline fibrous grains belonging to the transition zone T in Thornton's structural zone model. Polycrystalline CdS films show a strong <0001> preferred orientation and have a compact columnar structure belonging to Thornton's zone 2. ZnS and CdS films have a refractive index ranging from 2.1 to 2.25 and from 2.15 to 2.35, respectively.