Quantum conductors formation and resistive switching memory effects in zirconia nanotubes

Abstract

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 (V_O). For Zr/ZrO₂/Au memristors, resistive switching mechanisms to be sensitive to the migration of V_O 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.