Magneto-optical methods were applied for investigating the properties of Co/Cu/Co spin-valves deposited on Si substrate. The effects of electron transport and irradiation on remagnetization of such ferromagnetic (spin-valve)/semiconductor structures were studied for various thicknesses of ferromagnetic and non-magnetic layers.

Ultrathin composite ZnO/polyaniline (PAN) films were deposited from organic solutions on silicon and ITO substrates using wet layer-by-layer self-assembly technique. The film growth process was characterized by transmission electron microscopy, ellipsometry, atomic force microscopy, IR and UV-visible absorbance and photoluminescence spectroscopy, and electrical measurements. The Si substrates were pre-treated by chemical oxidation. Multilayer films were grown by sequential immersion of the substrate in an ethanolic ZnO sol and PAN solution in dimethyl formamide. The first adsorption cycle resulted in well-packed monoparticulate ZnO layer almost completely covering the substrate, which predetermined the regular growth of densely packed and quite smooth ten-layer ZnO/PAN film. Photoluminescence and IR data assumed chemical interaction between the components in neighbouring layers. The multilayer (ZnO/PAN)9ZnO film sandwiched between ITO and Pt electrodes exhibited strong photoelectrical response while both the components were photoelectrically inactive in our experimental conditions. The reversible conversion from insulating to conducting state was observed under irradiation by light with a wavelength below 350 nm.

Unilamellar colloids of graphite oxide (GO) were prepared from natural graphite and were grown as monolayer and multilayer thin films on cationic surfaces by electrostatic self-assembly. The multilayer films were grown by alternate adsorption of anionic GO sheets and cationic poly(allylamine hydrochloride) (PAH). The monolayer films consisted of 11-14 Angstrom thick GO sheets, with lateral dimensions between 150 nm and 9 mu m. Silicon substrates primed with amine monolayers gave partial GO monolayers, but surfaces primed with Al13O4-(OH)(24)(H2O)(12)(7+) ions gave densely tiled films that covered approximately 90% of the surface. When alkaline GO colloids were used, the monolayer assembly process selected the largest sheets (from 900 nm to 9 mu m) from the suspension. In this case, many of the flexible sheets appeared folded in AFM images. Multilayer (GO/PAH)(n) films were invariably thicker than expected from the individual thicknesses of the sheets and the polymer monolayers, and this behavior is also attributed to folding of the sheets. Multilayer (GO/PAH), and (GO/polyaniline)(n) films grown between indium-tin oxide and Pt electrodes show diodelike behavior, and higher currents are observed with the conductive polyaniline-containing films. The resisitivity of these films is decreased, as expected, by partial reduction of GO to carbon.