Structural and optical properties of (Li-TR(Nd, Er) co-doping sprayed ZnO thin films

Zinc oxide (ZnO) thin films co-doped with rare earth elements (RE = Nd 3 ⁺, Er 3 ⁺) and lithium (Li) were synthesized using the chemical spray pyrolysis technique. The structural properties of the films were investigated through X-ray diffraction (XRD), which confirmed the hexagonal crystal structure of the ZnO films, with a preferential orientation along the (002) plane. Atomic force microscopy (AFM) analysis revealed that the surface roughness of the films is influenced by the incorporation of rare earth elements into the ZnO matrix. Optical characterization showed that the films exhibited an average optical transmittance of 60%–80% in the visible region. Additionally, the optical band gap values ranged between 3.15 eV and 3.27 eV, indicating a slight variation due to the doping process. These findings demonstrate that co-doping with rare earth elements and lithium can significantly influence the structural, morphological, and optical properties of ZnO thin films, making them suitable for various optoelectronic applications.