Optical, structural, and morphological characterizations of synthesized (Cd-Ni) co-doped ZnO thin films

A well-prepared ZnO and (Cd-Ni) co-doped ZnO thin films are synthesized using the simple, inexpensive sol-gel method by immersing technique. The optical, structural, and morphological characterizations of (Cd-Ni) co-doped ZnO thin films are performed by employing UV-Vis spectrophotometry, X-ray diffraction (XRD), and the scanning electron microscope (SEM). The XRD patterns are consistent with those for standard hexagonal wurtzite structure. As the content of (Cd-Ni) co-dopant is increased from 0 to 8%, the transmittance spectra (T%) of thin films is decreased from 89 to 53%. In contrast, the reflectance spectra (R%) is increase from 7.8 to 18.2%. The values of the optical band gap E-g are found between 3.09 and 3.28 eV depending on the (Cd-Ni) co-doping ratio. A combination of Wemple-DiDomenico, Sellmeier, Spitzer-Fan models as well Drude model are implemented to estimate different optical parameters such as dispersion energy (E-d), zero-frequency refractive index (n(0)), Zero-frequency dielectric constant (epsilon(0)), the optical moment, High-frequency dielectric (epsilon(infinity)), the density of state (N-c/m*), Relaxation time (tau) as well the optical mobility (mu(opt)) and resistivity (rho(opt)). Technological constraints in fabricating (Cd-Ni) co-doped ZnO thin films include the variation of their properties as a function of deposition conditions such as doping concentration, nature and temperature of the substrate, technique of deposition and the nature of the chemical precursor used to control, in principle, the phase deposited and its morphology. ZnO thin films doped by transition metals have a lot of applications in optoelectronic devices such as solar cells, flat panel displays, photodetectors, gas sensors, and spintronics. Our comprehensive study paves the way to fabricate scaled devices based on (Cd-Ni) co-doped ZnO thin films.

Automated summary

A well-prepared ZnO and (Cd-Ni) co-doped ZnO thin films were synthesized using sol-gel method, with optical, structural, and morphological characterizations performed to analyze the impact of co-doping ratio on transmittance and reflectance.