Effect of annealing on the structural and opto-electrical properties of as-grown ZnO thin films by successive ionic layer adsorption and reaction (SILAR) technique

Abstract

The Zinc oxide thin films were grown on the amorphous glass substrate using Successive Ionic Layer Adsorption and Reaction (SILAR) technique at room temperature. The various preparative parameters were optimized to obtain good quality films. The as-grown films were annealed at 350° C for 2 h in air. The comparative study of the annealed and the as-grown thin films of ZnO were done for structural, optical and electrical studies. Polycrystalline nature was depicted from the x-ray diffraction (XRD) patterns. The peak intensity of as-grown ZnO thin films enhances after annealing. The average grain size calculated from XRD patterns was 17.66 nm for as-grown, while it increased to 24.66 nm after annealing. The band gap of as-grown ZnO thin films was relatively higher and was found to be 3.80 eV. After air annealing, the band gap decrease to 3.58 eV. The current-voltage characteristics show nearly ohmic behavior with decrease in the film resistance, after annealing in air. N-type conductivity was confirmed from the TEP measurements.The Zinc oxide thin films were grown on the amorphous glass substrate using Successive Ionic Layer Adsorption and Reaction (SILAR) technique at room temperature. The various preparative parameters were optimized to obtain good quality films. The as-grown films were annealed at 350° C for 2 h in air. The comparative study of the annealed and the as-grown thin films of ZnO were done for structural, optical and electrical studies. Polycrystalline nature was depicted from the x-ray diffraction (XRD) patterns. The peak intensity of as-grown ZnO thin films enhances after annealing. The average grain size calculated from XRD patterns was 17.66 nm for as-grown, while it increased to 24.66 nm after annealing. The band gap of as-grown ZnO thin films was relatively higher and was found to be 3.80 eV. After air annealing, the band gap decrease to 3.58 eV. The current-voltage characteristics show nearly ohmic behavior with decrease in the film resistance, after annealing in air. N-type conductivity was confirmed from ...