Synthesis of ZnO Nanocrystalline Powder From Ultrasonic Atomization Technique, Characterization, and its Application in Gas Sensing

Nanocrystalline zinc-oxide (ZnO) powders were prepared from the ultrasonic atomization method. An aqueous solution was atomized by using the ultrasonic atomizer operating at 2.1 to 2.3 MHz. The generated droplets were fed to the reaction furnace for pyrolysis. Nanocrystalline ZnO crystallites were collected by using a simple but novel trapping system, and prepared powder was characterized using X-ray diffractogram, transmission electron microscopy, scanning electron microscopy, and absorption spectroscopy. Nanostructured thick-film sensors of this powder were prepared by using the screen printing technique. The gas sensing performance of this film was tested. The sensor was found to be most sensitive to NH₃. The results were discussed and interpreted.