Room temperature ammonia gas sensing properties of NiO thin film

Abstract

In this work, nickel oxide thin films have been successfully deposited with a simple and low-cost spin coating method and annealed at 250⁰C. The structural and optical characterization of the NiO thin films was carried out using XRD, SEM, EDAX and UV-visible spectrophotometer. XRD pattern shows that all the prepared samples are in cubic structure and well-matched with JCPDS. From SEM, it is seen that all the films are uniform. From the transmittance spectra, the prepared samples are highly transparent, and the optical energy band gap was calculated from absorption spectra. These prepared samples were tested using static gas sensing set up to detect different reducing analyte gases including ammonia towards various ppm at room temperature. Ammonia is found to be good selective and highly sensitive. Response time and recovery time of the fabricated sensor were calculated and reported.