Optimization of AZO films prepared on flexible substrates

Transparent conductive Al2O3-doped zinc oxide (in AZO, Al2O3 content is similar to 2 wt%) thin films are deposited on flexible polyethylene terephthalate (PET) substrates, using radio frequency (rf) magnetron sputtering. The Taguchi method with an L (9) (3(4)) orthogonal array, a signal-to-noise ratio and analysis of variance (ANOVA) was used to determine the performance characteristics of the coating operations. Using grey relational analysis, the optimization of these deposition process parameters for AZO thin films with multiple characteristics was performed. The electrical resistivity of AZO/PET films is reduced from 2.6 x 10(-2) to 5.5 x 10(-3) Omega-cm and the visible range transmittance is > 83%, using the grey relational analysis. ANOVA results for the grey relational grade indicate that rf power and working pressure are the two most influential factors. The effect of the rf power (in the range from 30 to 70 W) and the argon working pressure (in the range from 0.90 to 1.1 Pa) on the morphology and optoelectronic performance of AZO films are also investigated. An analysis of the influence of the dominant parameters in the optimal design region is helpful for adjustment of the coating parameters.