Naphthenic Acid-Derived Nanocrystalline ZnO Films on Silica Substrate

Sol–gel-derived nanocrystalline ZnO thin films on silica glass substrates were prepared by using a zinc naphthenate precursor. As-deposited films were heat treated at 500, 600 and 700°C for 30 min in air. The ZnO films were analyzed by X-ray diffraction, field emission—scanning electron microscope, scanning probe microscope, and ultra violet—visible—near infrared spectrophotometer. With an increase in heat treatment temperature, the peak intensity of (002) plane increases. No evidently aggregated particles are present. All the films exhibit a high transmittance (>80%) in visible region and show a sharp fundamental absorption edge at about 0.38–0.40 μm. The estimated energy band gap for all the films are within the range reported for films and single crystal.