Role of substrate temperature on the properties of Na-doped ZnO thin film nanorods and performance of ammonia gas sensors using nebulizer spray pyrolysis technique

•Na-doped ZnO films deposited on glass by nebulizer spray pyrolysis (NSP) method.•NSP method for large area coatings and good results as compared with other methods.•HR-SEM studies reveal the formation of Na-doped ZnO films consisting of nano-rods.•Na-doped ZnO films ensure their stability and suitability for gas sensors.

Sodium doped zinc oxide (Na:ZnO) thin films were deposited on glass substrates at substrate temperatures 300, 400 and 500 °C by a novel nebulizer spray method. X-ray diffraction shows that all the films are polycrystalline in nature having hexagonal structure with high preferential orientation along (0 0 2) plane. High resolution SEM studies reveal the formation of Na-doped ZnO films having uniformly distributed nano-rods over the entire surface of the substrates at 400 °C. The complex impedance of the ZnO nano-rods shows two distinguished semicircles and the diameter of the arcs got decreased in diameter as the temperature increases from 170 to 270 °C and thereafter slightly increased.

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