Sabrina , Roguai2026-09-292026-09-292025http://dspace.univ-khenchela.dz:4000/handle/123456789/11513This thesis focuses on the detailed investigation of the structural, optical, electrical, photocatalytic, and photodetector properties of doped ZnO thin films synthesized using the sol-gel dip-coating method. Two doping strategies were studied: erbium (Er) doping and lithium (Li) co-doping combined with secondary elements such as Mg, La, and Al. X-ray diffraction (XRD) confirmed the hexagonal wurtzite structure for all films. At higher Er concentrations (10% and above), a secondary Er-rich phase appeared, indicating the solubility limit of Er in the ZnO lattice. Scanning electron microscopy (SEM) showed that moderate Er doping (2–5%) improved film uniformity, while excessive doping led to porosity and defects. Photoluminescence (PL) results revealed enhanced near-band-edge emission with increasing Er content, and electrical measurements showed improved conductivity up to 10% Er doping. Photocatalytic tests using methylene blue demonstrated that 2% Er-doped ZnO performed best under UV light and sunlight irradiation. In the co-doped films, 1%Al–5%Li–ZnO exhibited the highest transmittance (92%) and the widest optical bandgap (3.46 eV). Meanwhile, 1%La–5%Li–ZnO showed the best electrical conductivity and excellent UV photodetector performance, with high photoresponsivity and a fast response time. Overall, Er doping mainly enhances the optical and photocatalytic properties of ZnO, while Li-based co-doping with La or Al significantly improves electrical and UV detection performance. These results highlight the great potential of doped ZnO thin films for applications in optoelectronics, UV photodetectors, and environmental remediation.enThesis