Influence of the deposition cycles of ZnO thin films by SILAR deposition on the carbon monoxide gas sensor analysis

Zinc oxide as semiconductor thin film is very applicable for gas sensors. In this work, thin films were prepared by successive ionic layer adsorption and reaction (SILAR), which is a solution process using parameters as molar concentrations, times, and temperatures during deposition to control grain size, bandgap energy, and electrical resistance. This method follows the next steps; first, a glass substrate is immersed in zinc chloride-ammonia as cationic precursor, second step rinsing in deionized water, third step in hot deionized water at 90 degrees C as anionic precursor, and fourth step is rinsing in another deionized water to complete one cycle. Thin films were prepared at 50 and 100 deposition cycles and characterized by XRD, UV-Vis spectroscopy, SEM, and current-voltage measurements to study the structural, optical, morphological, and electrical properties, respectively. To evaluate its potential use as gas sensors, samples were exposed to carbon monoxide gas to evaluate its sensitivity.Graphical abstractFrom SILAR deposition to material characterization and sensor fabrication