Free-standing bilayered vanadium oxide films synthesized by liquid exfoliation of chemically preintercalated δ-LixV2O5·nH2O

A free-standing film composed of bilayered vanadium oxide nanoflakes is for the first time synthesized using a new low-energy process.

The Effect of Growth Parameters on Electrophysical and Memristive Properties of Vanadium Oxide Thin Films

We have experimentally studied the influence of pulsed laser deposition parameters on the morphological and electrophysical parameters of vanadium oxide films. It is shown that an increase in the number of laser pulses from 10,000 to 60,000 and an oxygen pressure from 3 × 10−4 Torr to 3 × 10−2 Torr makes it possible to form vanadium oxide films with a thickness from 22.3 ± 4.4 nm to 131.7 ± 14.4 nm, a surface roughness from 7.8 ± 1.1 nm to 37.1 ± 11.2 nm, electron concentration from (0.32 ± 0.07) × 1017 cm−3 to (42.64 ± 4.46) × 1017 cm−3, electron mobility from 0.25 ± 0.03 cm2/(V·s) to 7.12 ± 1.32 cm2/(V·s), and resistivity from 6.32 ± 2.21 Ω·cm to 723.74 ± 89.21 Ω·cm. The regimes at which vanadium oxide films with a thickness of 22.3 ± 4.4 nm, a roughness of 7.8 ± 1.1 nm, and a resistivity of 6.32 ± 2.21 Ω·cm are obtained for their potential use in the fabrication of ReRAM neuromorphic systems. It is shown that a 22.3 ± 4.4 nm thick vanadium oxide film has the bipolar effect of resistive switching. The resistance in the high state was (89.42 ± 32.37) × 106 Ω, the resistance in the low state was equal to (6.34 ± 2.34) × 103 Ω, and the ratio RHRS/RLRS was about 14,104. The results can be used in the manufacture of a new generation of micro- and nanoelectronics elements to create ReRAM of neuromorphic systems based on vanadium oxide thin films.

Electrophysical properties of vanadium oxide films deposited by reactive magnetron sputtering

The aim of this work was to study the effect of the gas composition during sputtering on the electrophysical properties of vanadium oxide films deposited by pulsed reactive magnetron sputtering of a vanadium target in an Ar/O2 medium of working gases.The dependences of the magnetron discharge voltage, deposition rate, resistivity, temperature coefficient of resistance (TCR), and the band gap of vanadium oxide films on the oxygen concentration in the gas mixture are obtained. It was found that amorphous films of vanadium oxide are formed during reactive magnetron sputtering. It is shown that the properties of the deposited vanadium oxide films have a strong dependence on the oxygen concentration in the Ar/O2 gas mixture, which is associated with the formation of a mixture of various intermediate vanadium oxides in the film. It was found that from the point of view of using vanadium oxide films as thermosensitive layers of microbolometers, the films must be deposited at oxygen concentrations in the gas mixture of 17 to 25 %. At the given oxygen concentrations without heating the substrates, vanadium oxide films with a resistivity (0.6–4.0)·10-2 Ohm·m, TCR 2.2–2.3%/°C and a band gap for direct transitions of 3.7–3.78 eV. The obtained characteristics make it possible to use these films as thermosensitive layers of microbolometers.