In this article, using the Tauc model, the absorption spectrum fitting method was applied to estimate the optical band gap and width of the band tail of the CdSe nanostructural films that requires only the measurement of the absorbance spectrum, and no additional information such as the film thickness or reflectance spectra is needed. Samples are prepared by chemical bath deposition method. Fabricated nanostructural thin films are thick but are composed from nanoparticles.

Cadmium selenide nanoparticle films were deposited on usual glass substrate by chemical bath deposition method. Temperature dependence of dc conductivity of the present samples was studied. In the nanocrystalline materials due to small size of grains and confined charge carriers, the electronic states near the Fermi level are localized. When states are localized, the conduction occurs by hopping of carriers between the occupied and unoccupied localized states. Variable range hopping was identified as a predominant conduction mechanism and occurs above room temperature. The density of localized states near the Fermi level was observed to increase with increase of average grain size in the film.

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A theoretical approach based on a tight-binding model is developed for studying the effects of finite concentration gas adsorption (for what are known as diatomic, triatomic and quadratomic gas molecules in the general forms denoted by XY, XY2 and XY3, respectively) on electronic properties of armchair graphene nanoribbons (AGNRs). To consider the edge effects on electronic properties of pure AGNRs for the first time, two hopping parameters, for hydrogen–carbon and carbon–carbon nearest neighbor hopping, are considered. We found, for some specified values of hopping integrals and random on-site energies, that adsorbed molecule AGNRs act as donors or acceptors, which is consistent with reported experimental results for CO, NO2, O2, N2, CO2 and NH3 adsorption on graphene. Then by using these parameters and the coherent potential approximation, we investigated the effect of finite concentration gas molecule adsorption on the average density of states. Our results could be used to make p-type or n-type semiconductors by means of finite concentration adsorption of gas molecules or a gas sensor.

In this study nickel-carbon (Ni-C) nanocomposite thin films composed of Ni nanoparticles with different average sizes embedded in amorphous hydrogenated carbon, were prepared through the combination of radio frequency sputtering and plasma enhanced chemical vapor deposition techniques. Such samples were used as experimental models to study the three dimensional surface morphology properties in thin films by atomic force microscopy imaging and fractal analysis over square areas of 1 μm 9 1 μm. The deposition time was varied at 7, 10 and 13 min, respectively, to study changes in the properties of the obtained films. The studied samples exhibited fractal properties characterized by fractal dimensions dependent on the deposition time with values between 2.43 ± 0.01 and 2.71 ± 0.01.