Boron and fluorine doped ZnO films obtained from zinc chloride precursor via chemical spray pyrolysis

Both boron (1, 2 and 3 at %) and fluorine (1, 3, 5 and 7 at %) doped zinc oxide thin films (ZnO:B:F) were fabricated using zinc chloride precursor by airbrush spray pyrolysis technique on glass substrates. X-ray diffraction (XRD) measurements show that all ZnO:B:F films have hexagonal wurtzite structure with a preferential growth along the [0 0 2] direction on glass substrates. Scanning electron microscope (SEM) results show that the morphologies of all doped films have a regular hexagonal shape. The optical measurements reveal that ZnO:B:F films have a direct band gap and optical energy gaps are increasing with boron and fluorine concentration. The optical transmittance of B and F doped ZnO films is measured very low due to columnar structure of prepared films. Moreover, it has been observed that the doping of ZnO films with boron and fluorine decreases the electrical resistance, and the lowest resistances of films were observed at 1%B–3%F and 2%B–3%F concentrations.