Distribution of nickel in zinc oxide nanowalls on sapphire substrate investigated using atom probe tomography

ZnO nanowall was synthesized using Ni catalyst and studied by atom probe tomography. Two regions of interest, one without and one with NiO, in ZnO nanowall were prepared. Ni simultaneously diffused with Zn during the formation of interlayer in the reaction between sapphire and ZnO. Atom probe tomography revealed Ni contents of about 1.09 and 1.33 at.% in the interlayers without and with NiO, respectively. The spinel structure of the ZnAl2O4 interlayer provides numerous octahedral sites into which Ni was doped.