Expanded solubility and densification behavior of Li-Ga co-doped ZnO

The effects of Ga3+ and Li+ co-doping on the solubility limits and densification behavior of ZnO were examined. When Ga and Li were co-doped at a 1:1 ratio, the overall solubility of Ga and Li increased to approximately 40 at% (20 at% of Ga+20 at% of Li). The lattice parameter decreased with increasing Ga and Li content. Pure ZnO showed a single densification curve, of which densification began at 600 °C. On the other hand, when Ga and Li were co-doped in ZnO, some retardation of densification was observed and densification began at approximately 800~900 °C. Hall-effect measurements of the co-doped ZnO specimens showed n-type semiconducting behavior as well as a decrease in the electrical conductivity with increasing Ga and Li content. The changes in the lattice parameter and microstructure of the ZnO were also examined as a function of the Ga and Li content.