Controlled synthesis of ZnO nanorods and layered double hydroxide nanocom-posites using a composition-modulated seed layer

We report the structural evolution of ZnO nanorods (NRs) and ZnAl layered double hydroxide (LDH) hybrid nanostructures fabricated by a simple hydrothermal method. The morphology of the hybrid nanostructures depended on the composition of the single seed layer of Al-alloyed ZnO (AZO) with different ratios of Al and Zn, which was grown by atomic layer deposition method. When the AZO seed layer was Al rich, the surface was mainly covered by the ZnAl-LDH structures. As the Al content decreased, the ZnO NRs dominated the hybrid nanostructures and pure ZnO NRs were finally formed when Zn-rich AZO or ZnO layers were used as a seed layer. A morphological evolution mechanism is suggested based on the different solubility of the sacrificial AZO seed layers, which depends on the Al content because the isoelectric point is larger in the ZnO than in the Al₂O₃.