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The influence of an intense electron beam on a nonstoichiometric oxide HfOx () layer of a TaN/HfOx/Ni memristor on its electrophysical properties is studied. It is found that the crystalline h-Hf, m‑HfO2, o-HfO2, and t-HfO2 phases are formed in the HfOx film under this impact. It is established that memristors demonstrate resistive switching at certain electron fluence values. At the same time, such memristors have resistive switching voltages several times lower than those of unirradiated memristors. In addition, they exhibit a multiple decrease in the spread of resistive switching voltages, as well as resistances in low- and high-resistance states. The current–voltage curves of the obtained memristors indicate that the charge transport in them is described by the space-charge-limited current mechanism. [ABSTRACT FROM AUTHOR]

Currently, a new generation of high-speed, information-intensive resistive memory based on nonstoichiometric dielectrics is being developed. The electron structure of nonstoichiometric silicon oxide SiOx is set by the value of parameter x. It is found that the treatment of thermal SiO2 in hydrogen plasma electron cyclotron resonance leads to the enrichment of silicon oxide with excess silicon, which in turn leads to the appearance of electron and hole traps in SiOx. SiOx conductivity is bipolar: electrons are injected from negatively biased silicon and holes are injected from positively biased silicon. Cathodoluminescence (CL) experiments confirm the assumption that the traps in SiOx are due to the excess silicon. p++-Si(100)/SiOx/Ni memristor metal-dielectric-semiconductor (MDS) structures are fabricated based on the developed procedure for the preparation of nonstoichiometric oxide in hydrogen plasma of electron cyclotron resonance. Such structures have the properties of resistive switching of SiOx that do not require a forming operation. [ABSTRACT FROM AUTHOR]

The influence of oxygen content in active zirconium oxide layers on the electrophysical properties of TaN/ZrOx/Ni memristors is investigated. The [O]/[Zr] atomic ratio (x) in the oxide layers was varied in the range from 1.56 to 2.0 by changing the partial oxygen pressure during their deposition by ion-beam sputtering deposition. The ZrOx film compositions were analyzed using x-ray photoelectron spectroscopy and density functional theory simulations. The multiple resistive switching phenomenon in TaN/ZrOx/Ni memristors was found to occur in a certain range of x ≥ 1.78. With the x value decreasing in the oxide layers, the forming voltage of memristors decreased. Furthermore, at the lower edge of x values the switchable range, they no longer required forming. At the same time, as the x value decreased, the memory window (ION/IOFF ratio) also decreased from 5 to 1 order of magnitude due to an increase in the memristor conductivity in the high resistance state. In order to identify the underlying conduction mechanism of TaN/ZrOx/Ni memristors, their current–voltage curves in low and high resistance states were analyzed in the temperature range from 250 to 400 K for the samples with x = 1.78 (forming-free) and 1.97 (which required forming). It was found that, for both samples, the conductivity in the low-resistance state is characterized by the trap-free space-charge-limited current (SCLC) model, whereas the conductivity in the high-resistance state is characterized by the trap-mediated SCLC model. The possible origins of structural defects involved in the memristor conductivity and resistive switching are discussed based on the obtained results. [ABSTRACT FROM AUTHOR]

The luminescence spectra of non-stoichiometric zirconium oxide film series with different oxygen vacancies' concentrations show the blue photoluminescence band centered near a 2.7 eV peak. There is a broad band at 5.2 eV in the luminescence excitation spectrum for blue emission. The ab-initio quantum-chemical calculation gives a peak in the optical absorption at 5.1 eV for the oxygen vacancy in cubic ZrO2. It was concluded that the 2.7 eV blue luminescence excited near 5.2 eV in a zirconium oxide film is associated with the oxygen vacancy. [ABSTRACT FROM AUTHOR]