Using a Statistical Experimental Design Method to Confirm the Optimization of Al/Al Doped ZnO Double Layers

A conductive metal thin film Al is deposited as a buffer to form Al/AZO double layers. The Taguchi method, based on the Al thickness, annealing temperature and duration, is used to determine the optimum synthesis conditions. The quality and thickness of the layers are analyzed by field emission scanning electron microscopy. The atomic resolution microstructures and the interface between Al/AZO are observed using high resolution transmission electronic microscopy. The optoelectronic properties of the layers are measured using a four-point probe and UV–VIS-NIR spectrophotometer. Using the appropriate parameters as derived by the Taguchi method, it is verified that the optimized results correspond with the experimental results for this study. The thickness of the Al metal layer is about 10 nm and the double layers are thermally annealed for 10 min at 500°C; the best figure␣of merit (FOM) is calculated as 0.0375 (Ω−1).