Influence of deposition parameters and annealing treatment on the properties of GZO films grown using rf magnetron sputtering

In this study, transparent conductive films of gallium-doped zinc oxide (GZO) are deposited on soda-lime glass substrates, under varied coating conditions (rf power, sputtering pressure, substrate-to-target distance and deposition time), using radio frequency (rf) magnetron sputtering, at room temperature. The effect of the coating parameters on the structural, morphological, electrical and optical properties of GZO films was studied. This study uses a grey-based Taguchi method, to determine the parameters of the coating process for GZO films, by considering multiple performance characteristics. In the confirmation runs, with grey relational analysis, improvements of 14.1% in the deposition rate, 39.81% in electrical resistivity and 1.38% in visible range transmittance were noted. The influence of annealing treatment, in a vacuum, oxygen, and nitrogen gas atmospheres, at temperatures ranging from 130 to 190 °C, for a period of 1 h, was also investigated. GZO films annealed at 190 °C, in a vacuum, showed the lowest electrical resistivity, at 1.07 × 10⁻³ Ω-cm, with about 85% optical transmittance, in the visible region. It is likely that films grown at lower temperatures (190 °C) could be coated onto polymeric substrates, to produce flexible optoelectronic devices.