Novel Hydrothermal Synthesis of Flower Like ZnO Nanostructures and Investigation of their Gas – Sensing Properties

Flower like nanostructures of ZnO have been successfully fabricated by a novel hydrothermal technique. Various sample characterization methods, including XRD, FESEM, SEM, TEM, have been employed. The synthesised ZnO samples exhibited a well defined crystal structure of hexagonal phase. The average crystallite size for ZnO sensors was estimated to be 31 nm. The flower shaped nanorods were 84 nm in diameter and 1 µm in length. The response to the reducing gas NH3 was evaluated in terms of the operating temperature, sensitivity, response time/ recovery time of the ZnO-based gas sensor. At a working temperature of C, the lowest detection limit for ammonia gas was found to be 5 ppm.