Preparation and characterization of highly oriented NiO(200) films by a pulse ultrasonic spray pyrolysis method

Cubic nickel oxide (bunsenite) films with a preferred (200) orientation and an average grain size of 15 nm were deposited on Si(111) substrate by a pulse ultrasonic spray pyrolysis method. Aqueous ethanol solutions of nickel nitrate were ultrasonically nebulized and thermally deposited on Si(111) using an aerosol generator, which was operated at 2.5 MHz. The resulting films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy. Highly crystalline NiO films with (200) orientation were obtained at 360 °C substrate temperature from 0.05 M solution and 5 l min−1 carrier gas flow rate. All grains were seen to be elongated along one direction by AFM. The ratio (64.58%) of the oxygen adsorbed to the total O1s intensity indicated that the film deposited by this method was a good candidate for electrochromic films.