Aluminium as catalyst for ZnO nanostructures growth

TL;DR

This study demonstrates that aluminium can act as an effective catalyst for the growth of ZnO nanowires via thermal evaporation, with growth characteristics influenced by parameters like oxygen pressure and Al seed density.

Contribution

It introduces aluminium as a novel catalyst for ZnO nanowire growth and analyzes how growth conditions affect nanowire orientation and crystallinity.

Findings

NWs density increases with Al seed density.

Oxygen pressure influences nanowire orientation and crystallinity.

Growth likely occurs via vapor-solid-solid (VSS) mechanism.

Abstract

We report the growth of Al-catalysed ZnO nanowires (NWs) using a thermal evaporation technique.Before the growth, the substrates were covered with a distribution of Al nano-island that act as seeds. We found that the density of NWs increases as the density of seeds is increased, confirming the catalyst properties of Al. The critical parameters of growth are the substrate temperature, oxygen partial pressure and the thickness of the initial Al layer from which the seeds are formed. The results showed that the oxygen pressure has a strong influence on the structural characteristics: the nanowires exhibit a preferential orientation in the (00l)-planes when they are grown at low oxygen flow, and they become polycrystalline when a high concentration of oxygen in the flow is used. We consider that the growth occurs via a vapor-solid-solid (VSS) process as the predominant growth mechanism.