The effects of fluorine on the structural, surface morphology and optical properties of ZnO thin films

The optical and structural properties of fluorine-doped Zinc oxide (ZnO) thin films have been investigated. The X-ray diffraction spectra indicate that the films have polycrystalline nature. A ZnO single phase with a hexagonal wurtzite structure was observed in structure of the films. The grain size for the films was calculated using a well-known Scherrer's formula and the obtained values are in the range of 27–40 nm. The values of direct band gap Egd were determined and these values change with doped fluorine (F) content. The shift of absorption edge is associated with Burstein–Moss effect. The width of localized states in the optical band of the films change with F content and the EU values change inversely with optical band gap values of the films.