Zinc oxide due to specific electrical, optical and acoustic properties is the important semiconductor material, which has many various applications. There is growing interest in ZnO due to its potential applicability for optoelectronic devices such as light-emitting diodes, laser diodes and detectors for UV wavelength range. ZnO properties are very close to those of widely recognized semiconductor GaN. The band gap of ZnO (3.37 eV) is close to that of GaN (3.39 eV) but ZnO exciton binding energy (60 meV) is twice larger than that of GaN (28 meV). Optically pumped UV lasing have been demonstrated at room temperature using high textured ZnO films. The excitonic gain close to 300 cm -1 was achieved. ZnO thin films are expected to have higher quantum efficiency in UV semiconductor laser than GaN. The physical properties of ZnO are considered. PEMOCVD technology was used to deposit piezoelectric and highly transparent electroconductive ZnO films. Their properties are discussed. The experiments on polycrystalline ZnO films deposited by RF magnetron sputtering at different partial pressure of oxygen are presented. AFM images were studied in tapping mode for deposited films. The investigated films were dielectric ones and had optical transparency within 65-85% at thickness in the interval 0.2-0.6 µm.

A brief review of research papers on some diluted magnetic semiconductors is given. Experimental results on the study of the ferromagnetic state in the most promising materials for use in spintronics are presented.

Chemical and phase composition, magnetic susceptibility, SIMS, magnetic force microscopy, and neutron diffraction data for Ge1−x−ySnxMnyTe, InSe⟨Mn⟩, and ZnO⟨Co, Mn⟩ single crystals are investigated over a wide range of temperatures and magnetic fields. For Ge1−x−ySnxMnyTe the existence of ferromagnetic (FM) ordering with a Curie temperature TC∼50K, due to an indirect exchange interaction between Mn ions via the degenerate hole gas, is established. It is shown that at T<50K the ferromagnetic regions of the crystal form a spin-glass phase. In InSe⟨Mn⟩ it is found that hysteresis loops of the magnetic moment M(H) are observed up to 350K. They attest to the existence of ferromagnetic ordering, which is apparently due to ferromagnetic clusters in which a superexchange of the Mn ions via the Se anions is proposed, and to an indirect interaction via the 2D electron gas. At T<70K a period doubling of the magnetic sublattice of α-MnSe second-phase inclusions is observed, and their distribution in the layered structure of the InSe⟨Mn⟩ host matrix has a regular character, forming a self-organized FM∕AFM superlattice. In ZnO⟨Co, Mn⟩ the temperature dependence of M obeys a Curie law. When the solubility limit of Co in ZnO is exceeded, hysteresis loops are observed as a consequence of the appearance of a ferromagnetic second phase. In ZnO⟨Mn⟩ samples and also in some ZnO⟨Co⟩ samples with Co content below the solubility limit an antiferromagnetic (AFM) interaction takes place.

The wide range of gas sensor application, in particular, in a mining industry for detection of outflow of gases, the control of gas emissions over an atmosphere at the industrial enterprises, in housing and communal services, in home appliances makes actual the review. As the systematized analysis of gas sensor based on ZnO has not being carried out-this work is of interest for development of chemical sensors based on zinc compound with high sensitivity, selectivity and stability. The resistive type of gas sensor based on thin-film ZnO which possesses a number of advantages: high sensibilities, low cost, the small sizes, simple manufacturing techniques, provide definition practically all gases and vapors at low concentration is in detail considered. In additional, the gas concentration to be analyzed directly transformes to an electric signal, that considerably simplifies the circuit of measurement. In present paper the table of the basic characteristics of existing thin-film ZnO gas sensors is given, which evidently allows to estimate the characteristics of available gas sensor based on oxide zinc film.

Abstract:Thin films of ZnO were deposited by reactive thermal evaporation, r.f. magnetron sputtering and PEMOCVD. Crystal structure, surface morphology as well as ultraviolet photoluminescence at optical excitation were investigated. It is determined that ZnO films especially deposited by reactive thermal evaporation exhibit strong ultraviolet luminescence. We suggest that observed luminescence is obliged to recombination of excitons bound on two different defects.

Al-doped ZnO (AZO) thin films were deposited by magnetron sputtering layer-by-layer growth method on silicon and glass substrates at different substrate temperatures. The atomic force microscopy analysis shows that AZO films are very flat with average root-mean square roughness 2.3 nm. Energy dispersive X-ray spectroscopy analysis reveals that Al content in AZO films approx. 1 at. %. X-ray diffraction studies have shown that all aluminum doped ZnO films are polycrystalline ones having hexagonal wurtzite structure with c-axis oriented perpendicular to film plane (002). Optical