Preparation and properties for aluminum-doped zinc oxide powders with the coprecipitation method

Abstract

Zinc oxide powders of different Al doping contents (AZO) were prepared with the coprecipitation method from zinc nitrate solution and aluminum nitrate solution in this study. The effects of process parameters such as the Al doping content, calcination temperature and calcination time etc. on electric conductivity were examined quantificationally. The AZO powders had good electric conductivity than that of zinc oxide powders. The resistivity of the AZO powders significantly depended on the Al doping content, calcination temperature and calcination time. The minimum resistivity 179.2 Ω·cm was obtained from the 2 mol% Al doped powders in this work, which were prepared at the calcination temperature 1300°C for 2 h. The AZO powders were also characterized with the X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results show that when the Al doping content is less than 2 mol%, the Al3+ enters into the ZnO lattice to form the solid solution, and causes the current carrier increase and the resistivity drop, but the excessive Al3+ doping brings the ZnAl2O4 spinel phase generate, resulting in the resistivity increase.