Improvement of TiO2 memristor properties by α-particles irradiation A. S. Ilin, P. A. Forsh, Yu. V. Balakshin, B. S. Shvetsov, D. V. Gusev, et al. Applied Physics Letters, 2025 This paper investigates the effect of alpha-particle irradiation on the memristive properties of titanium oxide-based structures. Multilayer TiOx/Ti structures were fabricated by magnetron sputtering and subjected to alpha-particle irradiation with a fluence of 2 × 1012 ions/cm2. Defect formation was modeled using the Monte Carlo method. The memristive characteristics of the structures were studied before and after bombardment. Ion bombardment was found to increase the number of stable resistive states by nearly three times, extend the number of switching cycles by 1.5 times, and significantly enhance the ROFF/RON ratio. This optimization of memristive parameters is attributed to the formation of locally created defects.
Impedance Spectroscopy of Memristive Structures Based on Hafnium Oxide M. N. Martyshov, I. D. Kuchumov, B. S. Shvetsov, D. M. Zhigunov, A. S. Ilyin, et al. Nanobiotechnology Reports, 2025 Memristive structures of Ti/HfO2/Au/c-Si, which are characterized by high ductility, are studied using the impedance spectroscopy method. Impedance hodographs are obtained for several stable resistive states. An equivalent circuit is proposed that takes into account the change in the resistance of filaments during their growth and allows for a good description of the observed changes in the type of the hodograph. Using simulation, the numerical values of the equivalent-circuit parameters are calculated. It is shown that during the switching process a significant change in the capacitance of the structure occurs. The data obtained allow us to better understand the processes that occur in such structures during switching, and open up the possibility of creating elements in which both resistance and capacitance can be controllably changed simultaneously.
Parylene-based memristive crossbar structures with multilevel resistive switching for neuromorphic computing B. Shvetsov, A. Minnekhanov, A. Emelyanov, Aleksandr I Ilyasov, Y. Grishchenko, et al. Nanotechnology, 2022 Currently, there is growing interest in wearable and biocompatible smart computing and information processing systems that are safe for the human body. Memristive devices are promising for solving such problems due to a number of their attractive properties, such as low power consumption, scalability, and the multilevel nature of resistive switching (plasticity). The multilevel plasticity allows memristors to emulate synapses in hardware neuromorphic computing systems (NCSs). The aim of this work was to study Cu/poly-p-xylylene(PPX)/Au memristive elements fabricated in the crossbar geometry. In developing the technology for manufacturing such samples, we took into account their characteristics, in particular stable and multilevel resistive switching (at least 10 different states) and low operating voltage (<2 V), suitable for NCSs. Experiments on cycle to cycle (C2C) switching of a single memristor and device to device (D2D) switching of several memristors have shown high reproducibility of resistive switching (RS) voltages. Based on the obtained memristors, a formal hardware neuromorphic network was created that can be trained to classify simple patterns.
Stability of Quantized Conductance Levels in Memristors with Copper Filaments: Toward Understanding the Mechanisms of Resistive Switching O. Kharlanov, B. Shvetsov, V. V. Rylkov, A. Minnekhanov Physical Review Applied, 2022 Memristors are among the most promising elements for modern microelectronics, having unique properties such as quasi-continuous change of conductance and long-term storage of resistive states. However, identifying the physical mechanisms of resistive switching and evolution of conductive filaments in such structures still remains a major challenge. In this work, aiming at a better understanding of these phenomena, we experimentally investigate an unusual effect of enhanced conductive filament stability in memristors with copper filaments under the applied voltage and present a simplified theoretical model of the effect of a quantum current through a filament on its shape. Our semi-quantitative, continuous model predicts, indeed, that for a thin filament, the “quantum pressure” exerted on its walls by the recoil of charge carriers can well compete with the surface tension and crucially affect the evolution of the filament profile at the voltages around 1 V. At lower voltages, the quantum pressure is expected to provide extra stability to the filaments supporting quantized conductance, which we also reveal experimentally using a novel methodology focusing on retention statistics. Our results indicate that the recoil effects could potentially be important for resistive switching in memristive devices with metallic filaments and that taking them into account in rational design of memristors could help achieve their better retention and plasticity characteristics.
