H2 gas sensing applications of undoped and Fe-doped CuO thin films grown by USP

The pure and Fe-doped CuO thin films were successfully grown by using ultrasonic spray pyrolysis method (USP) onto glass substrates. The changes in structural, morphological, H2 gas sensor, and optical properties of the synthesized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible spectroscopy, photoluminescence (PL) spectroscopy, and gas detection analyses were carried out. XRD data showed that the synthesized nanostructures belonged to the monoclinic phase of CuO with predominant (002) and (111) plane orientations and the grain sizes vary between 54.19 and 41.73 nm. In the morphological inquiry, structures possessed mostly rod-like polyhedral shapes and semi-spherical formations especially after Fe doping. EDAX and XPS verified that all the aimed materials were present on the deposited thin films. Gas sensor measurements clearly hinted that the Fe doping could lead to notable differences in H2 gas sensing abilities of samples. In the PL spectroscopy, weakened emission peak intensities recorded owing to the fact that the added impurities into the CuO lattice structures, which had major luminescence peaks at about 555 nm. Lastly, the ultraviolet–visible spectroscopy study discovered that the Fe doping affected the optical characteristics and the optical energy band gap increased.