Copper doped nickel oxide gas sensor

Abstract

RF-reactive planar magnetron sputtering system was utilized to fabricate NiO:Cu nanostructured thin films of (1300 ± 70) nm thickness with different doping ratios (5.73, 10.42 and 14.84) at.%. The doping technique includes adding copper chips to the target (nickel) surface. The structural properties for all deposited nanostructure NiO:Cu thin films are tested using XRD method, reporting at 2θ angle of 43°, a preferred (200) peak reflection with a polycrystalline nature. Nanostructure with columnar rods for NiO:Cu thin film samples of densely packed appearance are revealed by SEM images. The AFM images show that the average particle size and average roughness became higher with rising the concentration of copper.NiO:Cu optical measurements of the films revealed that the transmittance and the energy gap decreases as the copper doping ratio increases. The sensitivity of NiO:Cu gas sensor increased with Cu ratio and richer NO2 gas concentration. The dopant samples showed the best value of sensitively for NO2 (95%) for copper ratio of 14.84%, 150 °C working temperature, and 350 ppm concentration of NO2 gas. The prepared NiO:Cu thin films that we achieved by RF sputtering technique not only provide an economical appropriate approach for the production of p-type electronics, but also opens a new window for developing complementary integrated circuits made from metal oxide semiconductors.