Preparation and characterization of solid-state sintered aluminum-doped zinc oxide with different alumina contents

Aluminum-doped zinc oxide (AZO) ceramics with 0− 2 ·5 wt.% alumina (Al2O3) content were prepared using a solid-state reaction technique. It was found that AZO grains became finer in size and more irregular in shape than undoped ZnO as the Al2O3 content increased. Addition of Al2O3 dopant caused the formation of phase transformation stacking faults in ZnO grains. The second phase, ZnAl2O4 spinel, was observed at the grain boundaries and triple junctions, and inside the grains. In this study, a 3-inch circular Al2O3 (2 wt.%)-doped ZnO ceramic target sintered at 1500°C for 6 h has a relative density of 99·8% with a resistivity of 1·8 × 10 − 3 Ω-cm. The AZO film exhibits optical transparency of 90·3% in the visible region and shows an electrical resistivity of 2·5 × 10 − 3 Ω-cm.