Enhancing the Conductivity of the Nanostructured ZnO Thin Film by Vacuum Annealing

Abstract

ZnO thin films were successfully synthesized using a facile chemical route and were characterized employing X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and photoluminescence (PL) analysis. The obtained precursor was spin-coated on Si(100)/SiO2 wafers, then the substrates were divided into two groups for the thermal annealing at ambient and vacuum conditions. Morphological characterization showed the formation of nanoflowers and porous structures at different annealing conditions. The effect of vacuum annealing on the current-voltage characterization of ZnO thin film has been presented to inspect the role of annealing condition in device fabrication. The electrical properties of the ZnO thin films were performed in the temperature range of 75–[Formula: see text]C. At [Formula: see text]C, the ambient annealed sample presents the current value of 10[Formula: see text][Formula: see text]A for 5[Formula: see text]V, and the vacuum annealed sample reaches the maximum current of 3.1[Formula: see text]mA for the same operating voltage. The presence of oxygen vacancies notably affects the electrical properties of ZnO thin films.