Influences of lead and magnesium co-doping on the nanostructural, optical properties and wettability of spin coated zinc oxide films

The quality and optical homogeneity of thin films are necessary for optoelectronic devices and semiconductor technology. The influence of Pb doping, Zn1−xPbxO (0≤x≤0.05), and Mg co-doping, Zn0.95−yPb0.05MgyO (0≤y≤0.05), on the microstructural properties, optical parameters and wettability of ZnO films were investigated. X-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM) results show that the films have polycrystalline and hexagonal structure with a preferred (002) orientation combined with wrinkle network structure for the Pb doped films. The crystalline quality is slightly enhanced with the Pb doping and then deteriorated after Mg co-doping. The influences of the crystallinity and chemical composition on the film wettability are studied. All films show transparency between 85-93%. The reflectance and optical band gap of ZnO films decrease for Pb doping and then increase with Mg co-doping. Well-known Swanepoel׳s method is employed to determine the refractive index (n) and film thickness (d). The influences of Pb and Mg co-doping on the Urbach energy and optical dispersion parameters are also discussed.