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Pure, Mg-doped and Co-doped ZnO nanostructures were grown by atmospheric pressure metal-organic chemical vapor deposition. The influence of magnesium and cobalt contained in ZnO on microstructure, cytotoxicity, and virucidal and antibacterial activities under non-irradiated conditions was investigated. The incorporation of Mg and Co impurities into the crystal lattice of ZnO nanostructures modifies their electronic structure, surface morphology, and the concentration of point defects, which have some influence on the biological activity of the prepared ZnO nanostructures. The addition of magnesium and cobalt to ZnO nanostructures did not inhibit the reproduction of type 2 adenovirus, but an increased virucidal action for Mg- and Co-doped ZnO nanostructures against influenza A (H1N1) virus (strain FM/1/47) was observed. The titer of influenza virus was reduced by 1.92 lg for Mg-doped ZnO nanostructures. At the same time, Co-doped ZnO nanostructures showed the best results: the titer reduction was 3.57 for ZnO-Co (10 wt%) and 3.14 lg for ZnO-Co (5 wt%), indicating their good virucidal action. All tested ZnO nanostructures exhibited toxicity towards E. coli cells. [ABSTRACT FROM AUTHOR]

The effect of annealing on the optical properties of zinc oxide nanostructures grown by atmospheric pressure metalorganic chemical vapor deposition on silicon substrates covered with a thin film of silver is investigated. It is shown that annealing at temperatures above 600 ℃ significantly reduces the concentration of oxygen vacancies, and as a result, the ratio of the integrated intensity of ultraviolet emission to visible is improved 4.3 times. As a result of further high-temperature annealing at 900 ℃, the excitonic emission peak at 378 nm in the photoluminescence spectra is observed to shift towards larger wavelengths to 380 nm. Simultaneously, a decrease in its half-width from 140 to 100 nm is observed, which indicates an improvement in the structural perfection of ZnO/Ag/Si nanostructures. At the same time, an additional band in the region of 475 nm appeared, which, as we suggest, is due to optical transitions from the levels of shallow donors to the acceptor level created by the diffusion of silver in the lattice of zinc oxide. Annealing of ZnO nanostructures grown on silicon substrates as well as Ag-coated Si substrates improves their structure and optical properties, but unfortunately, this leads to a reduction in the photocatalytic activity of prepared ZnO nanostructures. [ABSTRACT FROM AUTHOR]

Optical properties of ZnO films doped by Al in the range 0.5 to 7 at.% and deposited by atomic layer deposition were studied in visible and infrared spectral range. Spectral dependences of film optical permittivity were modeled with the Lorentz-Drude approximation resulting in ZnO:Al plasma frequency and plasma damping parameters. We observed changing electron effective mass from 0.29m0 to 0.5m0 with increasing electron concentration in the range (0:9-4)x1020 due to the phenomenon of conduction band non-parabolicity. Comparing the results of optical and electrical investigations we can see that the main scattering mechanism is the scattering on grain boundaries (its contribution is about 60%). [ABSTRACT FROM AUTHOR]

Undoped, nitrogen-doped and aluminum-nitrogen co-doped ZnO films were deposited on Si substrates by magnetron sputtering using layer-by-layer method of growth. X-ray photoelectron spectroscopy was employed to characterize electronic properties of undoped and nitrogen doped ZnO films. The effects of N and N-Al ncorporation into the ZnO matrix on the X-ray photoelectron spectroscopy core-level and valence-band spectra of the films were studied and discussed. [ABSTRACT FROM AUTHOR]

The spectral distribution of the quantum efficiency in thin-film CdS/CdTe solar cells is being investigated by taking into account the drift and diffusion components of photocurrent, recombination at the CdS-CdTe interface, the back surface of the CdTe absorber layer and in the space-charge region. The effect of uncompensated acceptor concentration, lifetime of minority carriers and surface recombination velocity on the charge collection efficiency are discussed. The losses caused by reflections and absorption in the CdS and indium tin oxide layers are also considered. [ABSTRACT FROM AUTHOR]

The photoresponsive structures prepared by magnetron sputtering of ZnO:N on p-Si substrates followed by vacuum evaporation of semi-transparent Ni film on ZnO surface were investigated. The mentioned structures show high sensitivity that sharply enhances with increase of applied voltage. Under a bias 5 V, the responsivities at λ = 390 and 850 nm are equal to 210 A/W and 110 A/W which correspond to the quantum efficiencies of 655 and 165, respectively. It is suggested that the observed high response is attributed to internal gain in phototransistor structure containing Ni/n-ZnO Schottky contact as emitter junction and n-ZnO/p-Si heterostructure as collector junction. [ABSTRACT FROM AUTHOR]