Structural, optical and electrical properties of F-doped ZnO nanorod semiconductor thin films deposited by sol-gel process

Abstract

Structural, optical and electrical properties of fluorine-doped ZnO nanostructure semiconductor thin films prepared by sol-gel spin coating method have been investigated. The thin films have polycrystalline structure with a preferential growth along the ZnO (0 0 2) plane. The grain size for the films was found to be in the range of 24-35 nm. Scanning electron microscopy (SEM) images clearly revealed that the 10% F-doped ZnO film was composed of nanorods. Transmittance spectra of the films indicate that the films have high transparency. The optical band gap and Urbach energy of the F-doped ZnO films vary with fluorine doping. The refractive index dispersion curve of 20% F-doped ZnO film obeys the single-oscillator model. The dispersion parameters, E-o and E-d were found to be 6.104 and 12.045 eV, respectively. For 10% F-doped ZnO film, temperature-dependent conductivity studies revealed that the conduction mechanism is changed from the thermally activated conductivity to the grain boundary scattering with increase in temperature