Formation of 2D Copper Oxide Nanostructures on Substrates Exposed to Glow Discharge Plasma

A conventional glow discharge was engaged in conducting a process of plasma-enhanced synthesis of 2D CuO nanostructures on a copper sample installed on a cathode exposed to oxidation for 30 min at 360 Pa of oxygen pressure and the temperature of 600 ℃. The sample was partially covered with a copper cap with an orifice (1 mm diam.) to remove the ion flux extracted from the glow plasma to the surface area, while other parts of the sample were exposed to the direct action of the plasma. SEM instruments allowed for founding that after 2 min treatment, an array of interconnecting nanodots with an average diameter of 200 nm, formed of substructures of lesser diameters, is grown along the boundaries of the CuO oxide layer. Then the samples treated for 30 min revealed the dense arrays of 2D nanosheets with sizes up to 20 μm. The arrays were similar for the protected and unprotected sample areas. TEM study revealed a periodic structure on the surface of the nanosheets, presented by a set of grooves up to 20 nm in width separated by a similar area. The sizes of the substructure were associated with the sizes of the nanodots, and an assumption of the formation of a frame of the nanosheets of 1D nanowires was made. The proposed growth mechanism was then analyzed and verified using the developed theoretical model of the CuO nanowires growth.