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Resistive switching and adaptive behavior of resistive state in response to electrical stimulation has been studied for the silicon oxide based memristive devices subjected to electroforming in the conditions of current compliance in comparison with the analogous memristive devices after electroforming without any current limitation. The limitation of current and temperature during electroforming affects the parameters of growing conductive filament ensembles and reduction-oxidation reactions resulting in a gradual character and a wide dynamic range of resistance change important for neuromorphic applications.

Bipolar resistive switching of the metal-insulator-semiconductor (MIS) capacitor-like structures with the inert Au top electrode and Si3N4 dielectric nanolayer (6 nm thick) has been investigated. The effect of highly doped n+-Si substrate is revealed related to the changes in semiconductor space charge region on the small-signal parameters of parallel and serial equivalent circuit models measured in the high- and low-resistive capacitor states, as well as under laser illumination. The increase in conductivity of semiconductor capacitor plate significantly reduces the charging and discharging times of capacitor-like structures.

Planar waveguides based on tungsten-tellurite glasses doped with erbium and ytterbium ions are created. Planar structures with a superimposed strip based on tungsten tellurite glasses were formed by methods of Radio Frequency Magnetron Sputtering and lithography. Waveguide operation up to 1.53 mkm was observed. Optical losses at a wavelength of 1.53 mkm in the test channel waveguides with a width of 15 μm are ~ 0.44 dB/cm. The dependence of the optical signal enhancement at a wavelength of 1.53 mkm on the pump power was investigated for different lengths of waveguide.

The structure of the electron current through an individual filament of a nanometer-sized virtual memristor consisting of a contact of a conductive atomic force microscope probe to an yttria stabilized zirconia (YSZ) thin film deposited on a conductive substrate is investigated. Usually, such investigation is performed by the analysis of the waveform of this current with the aim to extract the random telegraph noise (RTN). Here, we suggest a new indirect method, which is based on the measurement of the spectrum of the low-frequency flicker noise in this current without extracting the RTN, taking into account the geometrical parameters of the filament. We propose that the flicker noise is caused by the motion (drift/diffusion) of oxygen ions via oxygen vacancies within and around the filament. This allows us to estimate the root mean square magnitude i0 of the current jumps, which are caused by random jumps of oxygen ions, and the number M of these ions. This is fundamental for understanding the elementary mechanisms of electron current flowing through the filament and resistive switching in YSZ–based memristor devices.

The principles of ion-beam simulation of the effect of fast (fission) neutrons and high-energy protons based on medium-energy ion irradiation have been developed for the Au/Zr/SiO2/TiN/Ti capacitor-like memristive nanostructures demonstrating the repeatable resistive switching phenomenon. By using the Monte-Carlo approach, the irradiation fluences of H+, Si+ and O+ ions at the energy of 150 keV are determined that provide the ionization and displacement damage equivalent to the cases of space protons (15 MeV) and fission neutrons (1 MeV) irradiation. No significant change in the resistive switching parameters is observed under ion irradiation up to the fluences corresponding to the extreme fluence of 1017 cm−2 of space protons or fission neutrons. The high-level radiation tolerance of the memristive nanostructures is experimentally confirmed with the application of 15 MeV proton irradiation and is interpreted as related to the local nature of conducting filaments and high concentration of the initial field-induced defects in oxide film.

An array of cross-point memristive devices has been implemented on the basis of yttria-stabilized zirconia thin film for applications in prototypes of spiking neural networks. The resistive switching phenomena and the plasticity nature of such memristive devices are studied. Reproducible bipolar resistive switching and precise tuning of resistive state are demonstrated and used to implement the plasticity rule according to STDP (spike-timing-dependent plasticity) mechanism. STDP learning is found to be dependent on the memristor's initial resistive state value and discussed in terms of the finite conductance change in studied structures. Obtained results provide the foundation for autonomous neuromorphic circuits with unsupervised learning development.

The photoluminescence of various Si ion implanted oxide layers annealed at high-temperature has been studied in the range of 350–1500 nm. The set of investigated oxide materials includes thermal SiO 2 , deposited SiO 2 , Si 0.9 Ge 0.1 O 2 , GeO 2 films on silicon substrate, and sapphire wafers. The results are discussed in terms of generation and modification of the defect centers and nanoclusters formation taking into account several factors related to composition and structure of the original oxide matrices.

The photoluminescence (PL) of Si + -implanted SiO 2 thermal films and ( 1 1 ¯ 0 2 ) sapphire substrates was studied for wide ranges of ion doses and annealing temperatures ( T ann ). The regularities of the PL at 780 nm from Si nanocrystals (NC) embedded in SiO 2 matrix for T ann = 1000 – 1200 ° C are described based on a model that takes into account coalescence of nearest NCs and dependence of radiative recombination rate on the NC size. Two PL bands found in Si + implanted Al 2 O 3 before and/or after annealing ( T ann = 500 – 1100 ° C ) are compared with those from Ar + -implanted samples and referred to the emission from Si NCs and defects.

The principles of control of the luminescent properties of the Si + (150 keV) ion-synthesized system, composed of silicon nanoinclusions in a SiO 2 matrix, are considered. The influence of the ion dose, annealing regime and additional doping with phosphorus is investigated. It is shown that the intensity of the red/infrared photoluminescence peak (at ∼800 nm) non-monotonously changes with the dose. The optimum dose is shifted to smaller values with increasing annealing temperature (from 1000 to 1100 °C for an annealing time of 2 h). The highest intensity reached by the dose variation is nearly the same for both temperatures. Phosphorus doping increases the luminescence intensity for 1000°C, the effect of doping is lower for higher Si + doses. The physical nature of the features observed is discussed.