Copper oxide nanoparticles were obtained in the plasma of a low-pressure arc discharge. The effect of the partial pressure of oxygen (10-40%) on the physical properties of the deposited nanoparticles has been studied. X-ray diffraction analysis shows that the cubic structure of Cu2O changes to monoclinic CuO with increasing O2 pressure. The results of Raman spectroscopy further confirmed the phase variations of copper-based oxide nanoparticles. X-ray photoelectron spectroscopy confirmed the change in the binding energy in the oxidation state of nanoparticles. The optical band gap of the deposited Cu2O is 2.12 eV, while that of CuO is 1.79-1.82 eV. Keywords: vacuum arc, oxides, nanoparticles, plasma-chemical reactions.

Highly porous CuO films up to 1 μm thick consisting of vertically oriented nanowires ~ 50 nm in diameter were synthesized by copper evaporation in a vacuum arc discharge in an argon/oxygen atmosphere followed by deposition on heated substrates. The phase composition and polycrystalline nature of the films were confirmed by X-ray diffraction. On the example of gaseous hydrogen H2 at a sensor operating temperature of 300oC, sensory characteristics of CuO films were studied. The qualitative mechanism of the effect of gas on the electrical characteristics of the nanostructured CuO film is described. Keywords: copper oxide, vacuum arc, nanowires, gas sensor.