Characterization of transparent zinc oxide films prepared by electrochemical reaction

Transparent ZnO films were grown by galvanostatic cathodic deposition onto conductive glasses from a simple aqueous zinc nitrate electrolyte maintained at 335 K. The as-deposited ZnO films were characterised by FTIR, XRD, SEM, optical transmission and absorption studies, and measurement of sheet resistivity as a function of cathodic current density. The ZnO films prepared had a wurtzite structure and exhibited an optical bandgap energy of 3.3 eV which is characteristic of ZnO. At a low cathodic current density of 0.05 mA/cm2, ZnO films with excellent electrical characteristics were obtained. A 2 micron thick ZnO film with an optical transmittance of 72% was deposited by electrolysis for approximately 20 min at a cathodic current density of 10 mA/cm2. 18 refs.