Fabrication of zinc oxide thin film for ammonia gas sensor

Zinc Oxide (ZnO) thin films were grown on silicon n-type Si(111) substrate with a simple method namely pulsed laser deposition technique for the ammonia (NH3) gas sensor. The patterns of X-ray diffraction (XRD) showed Hexagonal structure of ZnO nano film. surface topography ZnO nano thin films were characterized by using atomic force microscopy (AFM). FE-SEM measurements showed a homogeneous pattern structure without cracks as spherical particles structure and flower-like structure formation were have appeared on the surface nano-structure of the ZnO. Energy dispersive x-ray analysis (EDX) use to identify elemental composition of ZnO thin films. EDX measurement showed that there is no impurities. Optical measurements were performed to measure the band gap by UV-visible spectroscopy. ZnO/Si exhibited the excellent response as NH3 sensor. The sensitivity of the NH3 gas sensor was measured as function of temperature. The sensitivity of the device increased from 26% to 99 % with temperature of the gas from 100 to 200 respectively.