Abstract Antimony doped tin oxide (ATO) thin films are deposited on corning glass substrate using the spray pyrolysis technique. The experimental parameters such as distance between the substrate and source (10-30 cm), substrate temperature (350-450°C) and atmospheres (Nitrogen and Forming gas) are varied to study their effect on the properties of ATO thin films. The ATO thin film annealed at 425°C exhibits the lowest electrical resistivity of 2.23×10-2 Ω-cm. Besides, the film annealed in the nitrogen atmosphere showed a less resistivity value of 9.06×10-3 (Ω-cm) than the forming gas atmosphere. The film doped with 3 at% of Sb revealed the highest figure of merit value of 11.45x10-2 Ω-1. The preferential orientation is observed at the (200) diffraction plane in all the cases from the structural studies. Furthermore, the intensity of the diffraction planes decreases as the temperature increases. The average transmittance of 75% is obtained for ATO thin films.

Abstract Bismuth (III) sulfide thin films are prepared on glass substrates by physical vapor deposition technique. Then, the films are annealed at different temperatures from 150 to 350°C with nitrogen and nitrogen-sulfur atmospheres, respectively. The effect of annealing temperature on the optoelectronic properties is investigated. The layers were characterized using ultraviolet-visible spectroscopy, XRD, Raman spectroscopy, EDS analysis and Hall effect. The film annealed at 250°C in a nitrogen-sulfur atmosphere exhibited the best condition with an initial thickness of 106 nm and band gap of 1.37 eV. Also, Bismuthinite phase was obtained, close to the stoichiometry with 59.95 and 40.05 at % for bismuth and sulfur, respectively. The charge carrier concentration of 6.9x1019 cm-3 with a n-type conductivity, the resistivity of 0.19 Ω-cm, and mobility of 0.44 cm2V-1s-1 are obtained.

Abstract Cadmium telluride (CdTe) nanoparticles were grown in the interior of a SnO2 transparent matrix by means of the r.f. sputtering technique. X-ray diffraction (XRD) patterns reveal that the CdTe quantum dots (QD) grow in the hexagonal wurtzite (W) phase. Diffraction data show that SnO2 is constituted by nanoparticles also, with size of the same order of the W-CdTe QD. The broad bands of the XRD patterns and the Scherrer formula allowed, by assuming a spherical shape, the W-CdTe QD size calculation, which have average diameters in the range 4.8 - 14.0 nm. These data were confirmed by electron microscopy images. Optical absorbance gives information to calculate the energy of the two lowest excitonic states (band gap). The Raman spectra show several broad bands in the range 100 - 200 cm-1, on which deconvolution allows separate five modes in the 100 - 200 cm-1 interval. The bands correspond to CdTe and tetragonal Te. The transversal optic (TO) and longitudinal optic (LO) modes of CdTe at the Γ point of the first Brillouin zone, for phonons in nanoparticles, follow the expected behavior if the radius of crystal decreases, taking into account that the selection rules for momentum conservation are relaxed.