Investigation of aluminum and gallium co-doped ZnO powders and their effects on the properties of targets

Aluminum and gallium co-doped ZnO (AGZ) powders were synthesized by the chemical co-precipitation method with the same Al doping concentration (3 at%) and different Ga doping concentrations (0–0.5 at%). The microstructure, lattice distortion and surface morphology of AGZ powders were investigated because the properties of targets were related to corresponding powders. Both AZO and AGZ targets were prepared by molding and atmospheric pressure sintering. The microstructure, morphologies, electrical properties and densification of sintered targets were also studied. The measured results showed that the grain sizes of AGZ powders are smaller than AZO powder, the former has a larger specific area, and the distribution of AGZ particles are more homogeneous, which are good for preparation of a high-density target. Besides, the extent of ZnO lattice distortion exhibits a downward trend with the increase of the Ga doping concentration. The AGZ target with appropriate concentration of Ga (0.3 at%) has the lowest resistivity of 2.518×10−3 Ω cm and the highest relative density of 99.2%. In general, the moderate Al–Ga co-doping proportion leads to finer grain size, lower resistivity, higher Hall mobility and higher sintered density.