The structural, composition and optical absorption properties of Cd1−xZnxS (CdZnS) thin films fabricated by the reactive diffusion of Zn in CdS have been investigated. These ternary compounds were characterized by x-ray diffraction (XRD), energy dispersive x-ray fluorescence and optical absorption measurements. It is established that thermal annealing of Zn/CdS structure at temperature (400 °C) lower than the melting point of Zn (418 °C) results in the concentration distribution of Zn in CdS film described by an erfc-curve (D = 5 × 10−14 cm2 s−1) and characterizing the free impurity diffusion from a constant source. In contrast to this, the concentration profile of Zn in CdS film at higher annealing temperature (570 °C) is not described by the erfc-curve and shows a nearly stepped form, which is characteristic of reactive diffusion. XRD patterns of Zn/CdS structures annealed at 570 °C showed diffraction peaks of ternary CdZnS compounds. Analysis of the absorption spectrum of such films indicates formation of CdZnS composition with the largest value of energy band gap up to 2.64 eV, exceeding the band gap of CdS (2.43 eV). It is concluded that interdiffusion in Zn/CdS structures at temperatures exceeding the melting point of Zn was accompanied by formation of Cd1−xZnxS ternary compounds. The band gap of this variable band structure changes from 2.64 eV in the near surface region to 2.43 eV (CdS) in the inner region of the film.

Titanium dioxide (TiO 2 ) thin films were prepared by spin coating technique of sol precursor on Corning 7059 glass substrates. Spectral transmittances of as deposited and annealed samples were measured in the range of 250 to 1100 nm. Optical band gaps were calculated from the Tauc plots and was found to be about 3.78 eV for the annealed samples at 500• C. X-ray diffraction patterns were performed with as deposited and annealed samples. By annealing the samples at 500• C in various annealing times, the structure has changed from amorphous to the anatase crystalline state. Variations of the band gap energy values of TiO 2 films with cobalt doping were also investigated. Cobalt doping decreased the band gap value of TiO 2 films down to 3.25 eV. X-ray diffraction patterns were also given for the doped samples.

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A series of undoped and p-doped a-SiC:H samples have been made in the framework of a research plan for obtaining high quality p-type window layers by "Plasma Enhanced Chemical Vapor Deposition (PECVD)" technique from the mixtures of silane ( SiH 4), methane ( CH 4) and diborane ( B 2 H 6) gases. For the optimization of the window layer, the dependence of the electrical (conductivity) and optical (band gap) properties due to altered ratios of methane and diborane gases were investigated. When the diborane gas ratio was changed from Y = 0.06 to Y = 0.24 with an increase of 0.06 steps at a constant of X = 0.948 methane gas ratio, the dark conductivity and optical band gap values changed from ~ 10-19 (Ω· cm )-1 to ~ 10-10 (Ω· cm )-1 and 2.542 eV to 2.178 eV, respectively, and between these values, the most appropriate layers can be selected.