Structure and Optical Properties of ZnO Thin Films Prepared by the Czochralski Method

Abstract

The zinc oxide seed film was coated on conductive glass (FTO) substrate by the Czochralski method, Zinc acetate and hexamethylenetetramine were used as raw materials to prepare growth solution, and then ZnO film was prepared by a low-temperature solution method. The effects of annealing temperature on the morphology, structure, stress and optical properties of ZnO films were studied. The thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectra (UV — vis), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). The results show that the films are ZnO nanorods. With the increase of annealing temperature, the diameter of the rod increases, and the nanorods tend to be oriented. The band gap of the sample obtained from the light absorption spectra first increases and then decreases with the increase of annealing temperature. When the annealing temperature is 350 °C, the crystallinity of zinc oxide film is the highest, the band gap is close to the theoretical value of pure ZnO.

Keywords

Czochralski method / ZnO film / annealing temperature / optical properties / micromorphology / internal stress