Al diffusion in ZnO Nanowalls Investigated by Atom Probe Tomography

Abstract

Synthesis of ZnO nanowall structures using Ni catalyst was studied. ZnO nanowalls were grown by vapour-liquid-solid method. Ni as being a catalyst in the formation of ZnO nanowalls provided nucleation sites for the nucleation and the growth of ZnO nanowalls. Even though the sapphire system with ZnO has the high stability, the reactions between ZnO nanowalls and the sapphire substrate formed a 10-nm-thick interlayer during ZnO nanowall growth. Moreover, during the growth of the ZnO nanowalls, diffusion of Ni and Al was not expected as the Ni-Sapphire system is known to be non-reactive. Atom-probe tomography revealed that Al and Ni diffused into the NiO interface and sapphire substrate. Al diffused along the interface generated by the growth of ZnO nanowall, but Ni diffused into the interlayer between ZnO and sapphire.