Copper-Doped Tin Oxide Thin Films Prepared by Sol-Gel Dip Coating Technique for CO Gas Sensing

Copper-doped tin oxide (Cu: SnO 2 ) thin films have been fabricated using the sol-gel dip coating technique with one, two, and three immersion cycles. This study aimed to investigate the influence of the number of immersion cycles on the structural, morphological, and optical properties of the films for their potential application in CO gas sensing. The thin films were characterized by means of electronic microscopies (SEM), X-ray diffraction (XRD) studies, and UV-Vis’s spectroscopy. X-ray diffraction (XRD) analysis studies the film's crystalline structure and phase purity. The SEM images showed that the films had a uniform and dense structure, with an increase in the number of immersion cycles. UV-Vis spectroscopy was conducted to investigate the optical properties of the films. Gas sensing measurements were performed to evaluate the CO gas sensing performance of the films. The results demonstrated that the films prepared with three immersion cycles exhibited the highest sensitivity (1137.70) to CO gas.