Effect of concentration on the properties of nitrogen-doped zinc oxide thin films grown by electrodeposition

Zinc oxide is one of the most researched semiconductors owing to the outstanding properties that make it useful in various industrial applications, such as solar cells and other optoelectronics. In this work, ZnO thin films were prepared in five different concentrations and doped with four nitrogen atoms from triethylene tetramine (TETA) to fabricate a ZnO for optoelectronic applications using an electrodeposition technique. The doped ZnO thin films were synthesized and deposited on ITO glass substrates. The deposited thin films were annealed at 400°Cfor 60min in a furnace under the same conditions. The thin films' optical, electrical, and surface morphological properties were characterized using UV–Vis Spectrophotometer, Four Point Probe (FPP), and Scanning Electron Microscope (SEM), respectively. The optical properties confirmed the film's suitability for various transparent device applications with a high optical transmittance of about 90% at the wavelength between 250 and 950 nm. The optical band gaps of 3.25 eV to 3.50 eV were obtained at ZnO concentrations from 0.2 M to 1.0 M. The SEM images depicted a polycrystalline nature of the films with irregular nanoparticle shapes across the substrates. Electrical results established the high conductivity of nitrogen-doped ZnO thin films, thereby making the thin films suitable as transparent conducting oxides for devices such as solar cells and optoelectronics.