Nanostructural features of anodic zirconia synthesized using different temperature modes

Nanotubular and nanoporous structures of ZrO 2 were synthesized by potentiostatic anodization with varying the temperatures of anode in the range of T A = 0 - 90 °C and electrolyte in the range of T El = 20 - 50 °C. It was shown that difference between T A and T El had significant influence on growth rate and morphology type of zirconia nanostructures. Optimal parameters of thermal modes for nanotubular ZrO 2 synthesis were discussed. © 2018 Institute of Physics Publishing. All rights reserved.Act 211 Government of the Russian Federation, contract № 02.A03.21.0006, supported the study. R.V.K. thanks RFBR research project № 18-33-01072 for support. A.S.V. and I.A.W. thank Minobrnauki initiative research project № 16.5186.2017/8.9 for support

Quantum Conductors Formation and Resistive Switching Memory Effects in Zirconia Nanotubes

The prospects of the development of non-volatile memory elements that involve memristive metal-dielectric-metal sandwich structures are due to the possibility of reliably implementing sustained functional states with quantized conductance. In the present paper, we have explored the properties of Zr/ZrO2/Au memristors fabricated based on an anodic zirconia layer that consists of an ordered array of vertically oriented non-stoichiometric nanotubes with an outer diameter of 30 nm. The operational stability of the designed memory devices has been analyzed in unipolar and bipolar resistive switching modes. The resistance ratio ≥105 between high-resistance (HRS) and low-resistance (LRS) states has been evaluated. It has been found that the LRS conductivity is quantized over a wide range with a fundamental minimum of 0.5G 0 = 38.74 μS due to the formation of quantum conductors based on oxygen vacancies (VO). For Zr/ZrO2/Au memristors, resistive switching mechanisms to be sensitive to the migration of VO in an applied electric field have been proposed. It has been shown that the ohmic type and space-charge-limited conductivities are realized in the LRS and HRS, respectively. Besides, we have offered a brief review of parameters for functional metal/zirconia/metal nanolayered structures to create effective memristors with multiple resistive states and a high resistance ratio. © 2021 IOP Publishing Ltd

Unidirectional synapse-like behavior of Zr/ZrO2-NT/Au layered structure

Zirconia nanotubular layer with an outer tube diameter 25 nm was synthesized by potentiostatic anodization. The Zr/ZrO2-NT/Au memristive structure is fabricated using stencil mask and magnetron sputtering techniques. Current-voltage characteristics are measured in full cycles of resistive switching with varying parameters of the applied harmonic voltage. An equivalent circuit with unidirectional electrical conductivity for the studied structure is proposed. Estimates of the electrical resistance of memristors in high-and intermediate resistivity states are performed. The high synaptic plasticity of memristors based on the Zr/ZrO2-NT/Au structure is shown. © 2018 IEEE

VIRTUAL INSTRUMENT DEVELOPMENT FOR STUDYING MEMRISTIVE STRUCTURES IN THE PULSE MODE

A virtual instrument for registration of resistive switching for memristive structure based on titanium dioxide was developed and tested. It was possible to adjust the exact series of pulses with a duration of 100 μs. As a result, a consistent change in the resistance of the memristor was obtained.Исследование выполнено при финансовой поддержке Министерства науки и высшего образования Российской Федерации в рамках Программы развития Уральского федерального университета имени первого Президента России Б.Н. Ельцина в соответствии с программой стратегического академического лидерства "Приоритет-2030"

The Reliability Estimation for Memristor Structures Based on Nanotubular Zirconia

Reliability of memristors based on nanotubular zirconia was studied. The endurance is estimated to be > 113 thousand cycles as well as the resistance ratio is > 3000. The devices are able to remain stable for > 9 days in high and low resistance states at room temperature.Исследование выполнено в рамках инициативного научного проекта FEUZ-2020-0059 Минобрнауки РФ

SYNTHESIS OF NANOPOROUS MEMBRANES OF ZIRCONIA BY ANODIZATION

An effective method of rapid growth of zirconia nanotubes by anodization was devel-oped. The idea is based on temperature gradient between the Zr-anode backside and electro-lyte to enhancing electrochemical reaction and ion mobility at the barrier layer. Nanotubular layer of zirconia with a thickness of 20 ± 1 μm were synthesized by anodic oxidation for 2 h in the electrolyte based on ethylene glycol with small amount of water and ammonium fluo-ride

THERMAL STABILITY OF QUANTUM CONDUCTIVE FILAMENTS IN NANOTUBULAR ZIRCONIA

Resistive memory cells based on a 1.7 μm thick zirconia nanotubular layer were fabricated. Conductance quantization was shown due to the formation of quantum filaments consisting of oxygen vacancies. The rupture of filaments was observed at 75 °C temperature.Работа выполнена при поддержке научного проекта Минобрнауки FEUZ-2023-0014

SPECTRALLY RESOLVED THERMOSTIMULATED LUMINESCENCE OF NANOTUBULAR ZIRCONIA AFTER UV IRRADIATION

Zirconia nanotubular layer was synthesized with potentiostatic anodization. Thermally stimulated luminescence measurements were carried out within the (300…700) K range after 300 nm UV irradiation. Estimation of kinetic parameters was performed. Oxygen vacancies formation was discussed.Исследование выполнено в рамках инициативного научного проекта FEUZ-2020-0059 Минобрнауки РФ

Resistive switching mechanisms of memristors based on nanotubular arrays of anodic zirconium dioxide

Синтезированы мемристорные сэндвич-структуры Zr/ZrO2-nt/Au диаметром 140 мкм на основе нанотубулярного слоя диоксида циркония толщиной 1.7 мкм и внутренним диаметром нанотрубок 55 нм. Проведена аттестация образцов методами сканирующей электронной и конфокальной микроскопии. Исследованы вольт-амперные характеристики полученных устройств в статическом и импульсном режимах резистивного переключения. Определены параметры резистивного переключения. Установлены механизмы проводимости, доминирующие в различных состояниях структуры. Продемонстрирована возможность формирования квантовых филаментов, состоящих из кислородных вакансий, в оксидном слое. Показана перспективность применения данных структур в качестве мемристорных элементов памяти.Memristor Zr/ZrO2-nt/Au structure based on the zirconium oxide nanotubular layer with the thickness of 1.7 μm and the nanotubes inner diameter of 55 nm was synthesized. Attestation of the samples was performed with the methods of scanning electron and confocal microscopy. Current-voltage curves of the fabricated devices in static and pulsed modes of resistance switching were studied. Conduction mechanisms that dominate in different structure states were established. The formation of quantum filaments which consist of oxygen vacancies was shown to be possible in the oxide layer. The perspective of using these structures as memristor memory elements was shown