Coalescence of ZnO nanowires grown from monodispersed Au nanoparticles

TL;DR

This study investigates how monodispersed Au nanoparticles influence the growth, merging, and optical properties of ZnO nanowires, revealing the role of nanoparticle density and electrostatic interactions in nanowire coalescence.

Contribution

It provides new insights into controlling nanowire merging phenomena through nanoparticle density and electrostatic effects during growth.

Findings

Nanowire diameter and density depend on Au nanoparticle density.

Merging occurs when nanowires reach a critical separation distance.

Green luminescence is observed in fused nanowires, originating from residual nanowire material.

Abstract

New insights into controlling nanowire merging phenomena are demonstrated in growth of thin ZnO nanowires using monodispersed Au colloidal nanoparticles as catalyst. Both nanowire diameter and density were found to be strongly dependent on the density of Au nanoparticles. Structural analysis and spectral cathodoluminescence imaging of the c-plane nanowire cross-sections reveal that thin isolated nanowires growing from the Au nanoparticles begin to merge and coalesce with neighbouring nanowires to form larger nanowires when their separation reaches a threshold distance. Green luminescence, which is originated from the remnants of constituent nanowires before merging, is detected at the core of fused nanowires. The distribution of nanowire diameters and green emission were found to be strongly dependent on the density of the Au nanoparticles. The merging phenomenon is attributed to electrostatic interactions between nanowire c-facets during growth and well-described by a cantilever bending model.