Ammonia gas sensing performance of Co/Ni co-doped CdS thin films by chemical bath deposition

Thin films of cadmium sulfide co-doped with (CdS) cobalt and nickel were deposited over a glass substrate by means of chemical bath deposition (CBD) method. The consequence of Co doping and Ni co-doped CdS on the structural, morphological, and magnetic properties of deposited films have been analyzed. Structural study of the pure and Ni co-doped CdCoS thin films showed hexagonal structures with the preferred orientation along (002) direction. The average grain size of pure CdS and Ni-co-doped CdS obtained by AFM is 0.35 µm and 0.25 µm, respectively. X-ray photoelectron spectroscopy (XPS) survey indicated the existence of Cd, S, Co, and Ni peaks beside C 1s and O 1s peak. All films exhibit high transmittance in the visible and near-IR regions, indicating that they are of higher quality. Additionally, the observed decrease in energy bandgap can be explained by the creation of localized states in deep energy levels as a result of adding dopants. The room temperature soft ferromagnetic behavior was obtained for Ni co-doped CdCoS thin films. Finally, the gas sensing studies were conducted with a two-point probe gas sensor setup for the detection of ammonia (NH3) gas, and all the performance characteristics were examined under ambient air/humidity conditions at room temperature. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.