Gas-phase clusterization of zinc during magnetron sputtering

The processes of gas-phase clusterization of zinc during dc magnetron sputtering of a zinc target in an argon atmosphere have been investigated. The influence of the working gas pressure and magnetron discharge current on the morphology and structure of the precipitates formed on substrates previously cooled to–50°С is studied. It is shown that dense textured (002)Zn layers with a columnar structure are formed at relatively low argon pressures in the chamber (P = 0.5 Pa) and low discharge currents (100 mA). X-ray amorphous deposits with a fractal coral-like structure arise on substrates at an extremely high argon pressure in the chamber (P = 5 Pa). An increase in the magnetron discharge current at an operating gas pressure of 5 Pa leads to the formation of polycrystalline layers on substrates; the intensity of the XRD peaks related to crystalline zinc increases with an increase in the discharge current. Possible mechanisms of the structural transformation of Zn deposits are considered.     

Formation of a ZnO–C Composite with a Nanocrystalline Structure

Technical Physics - The formation of a nanocrystalline composite of a ZnO–C system with simultaneous mechanical activation of a mixture of zinc oxide and graphite powders in a ball mill in an...     

ZnO-Based transparent electrodes: Optimization of composition and synthesis conditions,study of properties

We present the results of comparative studies of the characteristics of ZnO-based transparent conductive layers doped with gallium (GZO) and aluminum (AZO), grown by dc magnetron sputtering of ceramic targets at various substrate temperatures (T _sub). Particular attention is paid to the study of stability of electrical characteristics of layers under temperature and humidity.     

Epitaxy of ZnO Films on the (0001) Surface of Crystalline Substrates of Lanthanum–Magnesium Hexaaluminate LaMgAl11O19

Crystallography Reports - The morphology and structure of heteroepitaxial ZnO films deposited on the (0001) surface of crystalline substrates of lanthanum–magnesium hexaaluminate LaMgAl11O19...     

Effect of the Working Gas Pressure on the Structure of ZnO Layers

Crystallography Reports - Zinc oxide layers have been synthesized by magnetron sputtering of ZnO:Ga ceramic and ZnO:Ga + 10 wt % Zn cermet targets in an Ar atmosphere and by reactive sputtering of...     

UV-Sensitive Porous ZnO-Based Nanocrystalline Films

Crystallography Reports - Nanocrystalline porous ZnO films have been synthesized by thermal oxidation of amorphous zinc deposits with an anomalously developed surface, which were previously formed...     

Transformation of the Structure of ZnO–C Powders during Mechanical Activation and Spark Plasma Sintering

The processes of grinding and transformation of the structure of the ZnO–C powder mixture at the mechanical activation by ball milling in an inert atmosphere have been investigated. The mechanical activation of the ZnO–C powder mixture is shown to lead to the formation of graphene oxide shells on the surface of crushed zinc oxide particles. The influence of the duration of activation of powder mixtures on the dynamics of their compaction during spark plasma sintering and structure of the ceramics obtained has been investigated. It is established that an increase in the activation duration to 100 h leads to a monotonic decrease in the density of sintered ceramics. The carbon shell formed during sintering at ZnO grain boundaries is shown to have the structure of reduced graphene oxide.

     

Photoluminescence of erbium in polycrystalline ceramics and in crystalline film of erbium oxide

Structural, optical, and electric properties of Er₂O₃ films obtained from Er₂O₃ ceramic target by the method of vacuum electron-beam deposition on sapphire substrates have been investigated. Optical characteristics of the films are studied in the range from UV up to IR using techniques of absorption, reflection, and emission spectroscopy; specific resistance of the obtained films was also measured. After excitation with the radiation of semiconductor diode laser at 980 nm, IR glow has been obtained at room temperature at the wavelength of approximately 1550 nm from Er³⁺ ions in polycrystalline ceramic target and in crystalline films. In addition, fluorescence was observed, in the visible range of spectrum, from ceramic target; this fluorescence corresponds to two-step mechanism of excitation with frequency up-conversion.     

Synthesis of TiO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>-based ceramics by plasma spraying

Structure of ceramics obtained by the plasma spray deposition of spherical TiO₂ powders has been investigated. An electron microscopy study of the surfaces and cross sections of particles in the initial powder and of the deposited ceramic coatings was performed. X-ray diffraction and Raman scattering data proved that the coatings were mainly structured as rutile. In addition, Raman and X-ray diffraction data have revealed an amorphous phase, an anatase phase, and non-stoichiometric phases Ti₈O₁₅, Ti₁₀O₁₉, Ti₇O₁₃, etc. being present in the coatings. The observed suppression of (011) and (111) XRD peaks and an increased intensity of (110) peak are indicative of a predominant orientation of grains in the synthesized ceramics. Mechanisms of formation of the complex coating structure are discussed.     

Effect of annealing on the optical and electrical properties of ZnO:Er films

The effect of dopant concentration and annealing in the oxidizing atmosphere on the structural, optical, and electrical properties of ZnO:Er films deposited on sapphire substrates by the electron-beam evaporation method is investigated. The optical and electrical properties of these films were studied by UV-VIS-IR absorption and reflection spectroscopy, photoluminescence, and resistivity measurements. Experimental results reveal that as-deposited ZnO:Er films have both high transmittance in the visible range and low electrical resistivity and can be used as efficient transparent conducting oxides (TCOs). These films annealed in the oxidizing atmosphere have a visible emission band which can be used to fabricate light-emitting diodes.