Nano Hybrids and Composites Vol. 28

Abstract: In a promising nanoelectronics device, namely, memristor based on metal oxides, there are many intermediate states with different conductivity between the limits of highly conductive and low-conducting states. These intermediate states can be used in the processes of associative learning of a neural network based on memristor synapses and simultaneous processing of input pulses, which consists in their weighing and summation in the neuroprocessor. By the method of simultaneous magnetron sputtering of two cathodes in a reactive oxygen environment, thin films of mixed oxides with a different mole ratio of titanium and aluminum were obtained. A method for obtaining a mixed oxide with a specified metal fractions by controlling the sputtering rates of cathodes using acoustic piezoelectric sensors is described. It is shown that the introduction of Al into titanium oxide improves the electrophysical characteristics of the memristor. The existence of an optimal fraction of Al dopant maximizing the memristor resistance ratio of the high-resistive and low-resistive states is established. The results indicate that the method of reactive magnetron deposition of mixed metal oxide by simultaneous sputtering of two cathodes provides a more uniform distribution of elements across the thickness of the active layer compared with the atomic layer deposition method. The uniform distribution is necessary to improve the stability of the memristor. It can be expected that in the memristors on mixed oxides Ti_xSc_1-xO_y, Hf_xSc_1-xO_y, Hf_xY_1-xO_y, Hf_xLu_1-xO_y, Zr_xSc_1-xO_y, Zr_xY_1-xO_y, Zr_xLu_1-xO_y an optimal dopant fraction corresponding to the maximally increased ratio of resistances in the high-resistance and low-resistance states will also be observed. Moreover, memristors on films with pure hafnium and zirconium oxides have a much larger range of resistive switching than titanium oxide.

Abstract: In this paper, we consider the technological features of the formation of thin ferroelectric films of lead zirconate titanate (PZT) by the method of plasma high-frequency reactive sputtering. The crystal structure, morphology and elemental composition of films deposited on silicon and oxidized silicon substrates are investigated. It is shown that the obtained PZT films have a perovskite structure and are polycrystalline with a predominant crystallite growth in the (110) direction. An automated test bench has been designed and manufactured for measuring the electrophysical parameters of ferroelectric films. The measured CV characteristics of the Ni/PZT/Si structure show the hysteresis caused by the polarization of the PZT film. It is noted that the asymmetry of the dependence of the spontaneous polarization on the applied voltage can be caused by the presence of surface states at the PZT/Si interface.

Abstract: This document describes the technology of manufacturing metal oxide films ZnO, SnO₂, Zn₂SnO₄ from aqueous solutions of the corresponding salts by spray pyrolysis. The modes and conditions of deposition of metal oxide films on hot (420 °C) glass substrates are given. The electrical parameters of the films were measured by the van der Pau method and by the Hall effect, the surface resistance was in the range from 140 to 85⋅10³ Ohm/. The band gap was determined by light absorption spectra and was within 3.2...3.5 eV. For all metal oxides, the n-type conductivity was determined using the thermosonde and the Hall effect.

Abstract: Lead sulfide films doped with cadmium and iodine ions were obtained by chemical bath deposition from the reaction mixture with thiourea that have thickness of up to 300 nm. An increase in cadmium iodide in the reactor from 5∙10^-5 to 5∙10^-3 mol/l is accompanied by a decrease in the period of the B1 cubic crystal lattice (space group ) from 0.59368 to 0.59355 nm, due to the replacement of Pb²⁺ ions in the PbS crystal lattice by a smaller size of ion Cd²⁺. The cadmium content in the synthesized layers varied from 0.4 to 2.8 at.% with a constant iodine concentration of 1.7–1.9 at.%. An electron microscopic study of the structure showed a decrease in the average crystallite size from 260 nm to 80 nm.

Abstract: The paper presents the results of mass spectrometric studies of laser-stimulated desorption from the surface of thin films based on organic copper phthalocyanine molecules with peripheral substituents on gallium arsenide substrates. Thin films (30-80 nm) of copper phthalocyanine with peripheral substituents in this regard are studied for the first time. The composition of particles desorbed from the surface of CuPc and CuPcF₁₆ films by laser radiation of various wavelengths of 532 nm and 1.06 μm with a pulse duration of 10 ns was studied. The identification of the main fragments of molecules present in the desorption stream was carried out. It was shown that under the action of laser radiation, the surface is leveled and the films are fragmented, followed by desorption of molecular fragments.

Abstract: The paper considers application of the physical and statistical approach to the issue of nanosystems reliability. A general method of solving the main equation in this approach is suggested and the solution in quadratures is obtained in one-dimensional stationary case. It is used to study the behaviour of entropy and the reliability function under certain assumptions. The cases of constant, linear, and quadratic degradation rates are analysed. In the first two cases the results correspond to physical intuition while in the last case (quadratic rate) the formal solution demonstrates counterintuitive behaviour. Numerical correlations between the distribution entropy dynamics and the reliability function are given.

Abstract: In this work, relations have been obtained that allow one to estimate the effect of pressure on the temperature of the liquid phase transition between different nanofilms and nanoparticles. It is shown that the external forces lead to a rise in phase transition temperature which should be considered during the contact-reactive soldering in electronics.

Abstract: Possible processes of the carbon isotopes fraction under hydrodynamic caviation at carbon-containing liquids are considered. We have made corresponding experiments with benzene, toluene and ethanol to provide carbon nanoforms with different crystal structures. Specific bonding forces for metals and n-diamond are modeled using developed numerical method. The task is to identify the key parameters affecting the pairs force potentials of carbon atoms and consider the application of the results to microelectronics and natural processes.

Abstract: The methods of Rutherford backscattering (RBS), X-ray photoelectron spectroscopy (XPS) and Raman scattering (RS) phase transformations in an amorphous carbon film deposited by electric arc method on a chromium-nickel alloy film were investigated. The formation of nanoparticles with a linear size of ~ 6 nm in a carbon film also was presented here.

Abstract: The model representations of the mechanism of electronic conductivity through InSb nanoparticle was formulated and analyzed in accordance with the theory of field emission. Based on the analysis of tunneling current-voltage characteristics of various methods of calculation obtained a consistent value of characteristic size InSb nanoparticles in the range from 18 to 22 nm. Analysis tunneling current-voltage characteristics (dark and light (stationary light)) allowed us to evaluate the legitimacy of the formulated model representations.