Properties of fluorine and tin co-doped ZnO thin films deposited by sol-gel method

Highly transparent and conducting fluorine (F) and tin (Sn) co-doped ZnO (FTZO) thin films were deposited on glass substrates by the sol-gel processing. The structure and morphology of the films are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) with various F doping concentrations. SEM images showed that the hexagonal ZnO crystals were well-arranged on the glass substrates and the HRTEM images indicated that the individual nanocrystals are highly oriented and exhibited a perfect lattice structure. Owing to its high carrier concentration and mobility, as well as good crystal quality, a minimum resistivity of 1 x 10(-3) - Omega cm was obtained from the FTZO thin film with 3% F doping, and the average optical transmittance in the entire visible wavelength region was higher than 90%. The X-ray photoelectron spectroscopy (XPS) study confirmed the substitution of Zn2+ by Sn ions and Room temperature photoluminescence (PL) observed for pure and FTZO thin films suggested the films exhibit a good crystallinity with a very low defect concentration. (C) 2013 Elsevier B.V. All rights reserved.