Defect-driven color emissions in nanostructured ZnO films synthesized by two-step ultrasonic spray pyrolysis

Abstract

Homogeneous and optimized nanostructured ZnO films were successfully synthesized by a simple technique. The growth conditions were modified from the change in synthesis temperature; from 300 to 450 °C, leading to significant modifications in ZnO morphology, luminescent properties and thicknesses of ZnO films. These structural and optical properties changes allowed emissions at different wavelengths. The color of emissions from ZnO films are according to defect levels of ZnO nanostructures. Photoluminescent results and CIE chromaticity analysis demonstrated three different emission bands: yellow-orange, green and cyan due to high concentration of Z_ni-V_Zn and CB-V_O transitions. This proposed synthesis suggests its integration into scalable fabrication process for obtain nanostructured ZnO films for luminescent devices.