Impact of withdrawal speed on the properties of CuO films deposited via sol-gel dip coating

The growing demand for superior gas sensors has led researchers to increasingly focus on materials characterization, given its critical role in enhancing gas sensing capabilities. In this study, different withdrawal speeds were investigated on the properties of CuO films deposited using the sol-gel dip-coating technique. The findings revealed that the optimal conditions for the CuO film were achieved at a withdrawal speed of 70 mm/min. The XRD results indicated that all CuO films exhibits pure CuO phase resembling higher crystallinity and larger crystallite sizes. Surface morphology from FESEM analysis revealed more uniform surfaces and well-developed flower-like structures. For AFM results, topology images showed a smoother surface with low roughness. Surface profiler measurements observed that the film thickness have direct relationship toward withdrawal speeds, showing an optimal thickness and thinner films are at lower withdrawal speed. By utilizing the four-point probe, electrical resistivity measurements revealed a higher quality of structural and surface properties of films consequently led to a decrease in electrical resistivity. The results indicate that CuO films deposited at 70 mm/min have favorable features for gas sensor applications, highlighting the importance of withdrawal speed in optimizing film properties towards sensor performance.