Lead-based ternary-chalcogenide thin films of the (PbTe)1−x(PbS)x system were obtained using the plasma-enhanced chemical-vapor-deposition (PECVD) technique under conditions of a nonequilibrium low-temperature argon plasma of an RF discharge (40.68 MHz) at a reduced pressure (0.01 Torr). High-purity elements were directly used as starting materials, namely Pb, S and Te. Plasma–chemical synthesis was carried out on the surface of c-sapphire and silicon substrate. The physicochemical properties of the films were studied using various analytical methods. The dependence of the Seebeck coefficient, resistivity and power factor on the structural properties and composition has been studied. The thermoelectric characteristics were found to be dependent on film composition. Upon the selection of optimal sulfur concentration, one can increase the power factor compared to single-phase PbS or PbTe films.
The magnetic properties and micromagnetic structure of [Co/Pt]10 multilayer magnetic films formed by independent variation of the Co and Pt layer thicknesses have been studied. The possibility of the film magnetization parameters manipulation was shown. It is found that the micromagnetic structure of the layers is significantly modified with a change in the thickness of the layers which correlates with the magnetization data. In particular, magnetic force microscopy revealed a system of magnetic skyrmions for a number of structures. The skyrmion density was found to be dependent on the growth conditions which in turn correlates with the shape of the magnetic hysteresis loop. Changing the thickness of the Co and Pt layers makes it possible to control the density of skyrmions in the range from 0.2 to 10.5 mkm-2. Keywords: micromagnetic structure, skyrmions, CoPt films, electron beam evaporation.
Lead-based ternary chalcogenide thin films of the (PbTe)1-x(PbS)x system were obtained by plasma-enhanced chemical vapor deposition technique (PECVD) under conditions of a nonequilibrium low-temperature argon plasma of an RF discharge (40.68 MHz) at a reduced pressure (0.01 Torr). High-purity elements were directly used as starting materials – Pb, S and Te. Plasma-chemical synthesis was carried out on the surface of of c-sapphire and silicon substrate. The physicochemical properties of the films were studied by various analytical methods. The dependence of the Seebeck coefficient, resistivity, and power factor on the structural properties and composition has been studied. The thermoelectric characteristics were found to be dependent on the film composition. Upon the selection of optimal sulfur concentration one can increase the power factor as compared to single phase PbS ot PbTe films.
Pulsed laser deposition in vacuum at 220°C of GaAs layers heavily doped with Mn and/or Bi has been used to form nanostructures on i-GaAs (100) substrates. It is shown that, for the electrical activation of manganese, it is expedient to use subsequent annealing with an excimer laser pulse with a wavelength of 248 nm and a duration of 30 ns. The structures show an anomalous Hall effect with a hysteresis loop on the magnetic field dependence up to a Curie temperature of about ~70 K. Negative magnetoresistance is observed up to temperatures of ≈150 K. Bismuth does not prevent the activation of Mn atoms during annealing and contributes to an increase in the coercive field of the GaMnAs ferromagnetic semiconductor.
It has been established that the physicochemical properties of structures based on iron silicides formed by ion implantation of iron ions into silicon depend significantly on the time of subsequent high-temperature annealing. Objects with different geometric parameters are formed on the surface and the roughness increases. Annealing at 1000oC in an Ar atmosphere is accompanied by a decrease in the content of the Fe-Si chemical bonds during the first 60 seconds. The reason for the drop in thermal conductivity with increasing annealing temperature is the formation of silicide complexes. Keywords: iron silicide, thermoelectric, ion implantation, chemical composition, X-ray photoelectron spectroscopy.