Ultrasonically synthesized nanocrystalline ZnO powderbased thick film sensor for ammonia sensing

Purpose The purpose of this paper is to show how to obtain better response, selectivity and fast response and recovery from nanocrystalline ZnObased gas sensors as compared to conventional materials. Designmethodologyapproach Nanocrystalline ZnO powders were prepared from the ultrasonic spray pyrolysis method. Aqueous solution of zinc acetate was atomized using ultrasonic atomizer. The aerosol generated was fed to the reaction furnace for pyrolysis. Nanocrystalline ZnO crystallites were collected using simple but novel trapping system. Thick film resistors of this powder were fabricated using screen printing technique. Findings Asprepared powder was studied using Xray diffraction, transmission electron microscopy and scanning electron microscopy to know structure, size of nanocrystallites and microtopography, respectively. Absorption spectroscopy is used to determine the band gap energy. The gassensing performance of this film was tested. Originalityvalue The sensor was found to be the most sensitive to NH3. It gives better response, selectivity and fast response and recovery as compared to conventional materialsbased thick films.