Infrared spectra of cholesteryl benzoates, ortho and para Br cholesteryl benzoates, para ethoxy cholesteryl benzoates in crystalline, cholesteric and isotropic states as well as in dilute carbon chloride solutions have been obtained. The behavior of absorption band of carbonyl group (C=O) stretching vibrations in cholesteryl benzoates was investigated. The results obtained are indicative of the strengthening of local intermolecular interactions in cholesteric phase.

The n-ZnO films doped with Ga to the content 2.5 at % are produced by pulse laser deposition onto the (0001) oriented single crystal sapphire substrates. The transmittance spectra of the ZnO films in the range from 200 to 3200 nm are studied in relation to the Ga dopant content. It is established that an increase in the Ga content shifts the fundamental absorption edge to the blue region, but reduces the transparency of the ZnO films in the infrared spectral region. The dependence of the band gap on the level of doping with Ga is determined. The photoluminescence spectra of the ZnO films doped to different levels are recorded. It is established that the PL intensity and peak position vary unsteadily with the level of doping. X-ray diffraction studies of the structure of the films are carried out. It is found that the crystallographic parameters (the lattice constant c) of the ZnO film depend on the Ga dopant content and the conditions of deposition of the films.

The thin films of zinc oxide have been produced by the pulse laser deposition method at various levels of gallium and nitrogen doping. To obtain the n-type films we used gallium doping with concentration of gallium from zero up to 5 at %. The dependence of photoluminescence of the epitaxial ZnO:Ga films on the concentration of gallium doping has been studied. An optimum range of the n-type ZnO films doping with gallium has been determined to obtain highly effective films from the viewpoint of realizing p-n transitions. This range, on the one hand, defines the maximal PL amplitude and, on the other hand, specifies the minimal specific resistance that corresponds to an interval of 0.125–1.000 at % Ga. To produce the p-type ZnO:(Ga, N) films, the ZnO targets with the content of GaN from zero up to 2 at % were used. N2O was used as a buffer gas. A difference is observed in the positions of the peaks of the emission lines of the photoluminescence spectra for the ZnO films, doped with gallium (Ga) and co-doped with gallium and nitrogen (N).

The thin films of zinc oxide have been produced at various levels of doping with gallium. The dependence of the ZnO film crystallographic parameters on the deposition process parameters has been established. The dependence of the photoluminescence spectra of films on the conditions of deposition has been investigated. A study has been made of the intensity, emission band width, and the value of Stokes shift of ZnO films.