Botryoidal growth of crystalline ZnO nanoparticles on a forest of single-walled carbon nanotubes by atomic layer deposition

Abstract

Atomic layer deposition (ALD) is a type of chemical vapor deposition method specially modified to grow thin films via a so called self-limiting growth mechanism. In spite of its excellent conformality due to inherent layer-by-layer growth behavior, the utilization of ALD is restricted mainly to the growth of thin films. In this article we demonstrate that ZnO nanoparticles can be grown with a botryoidal appearance by ALD using a forest of single-walled carbon nanotubes as the substrate, which only has a sparse amount of reactive sites for precursor chemisorption. The nanoparticles are fairly spherical and single crystalline with a wurtzite crystalline structure. The growth rate of the nanoparticles is roughly estimated to be ∼2.8 Å cycle⁻¹ which is around twice the growth rate of a conformal film on a flat substrate. The size of the nanoparticles is considerably uniform with a standard deviation of ∼18%.