Site selective synthesis of in situ Ni filled multiwalled carbon nanotubes using Ni(salen) as a catalyst source

TL;DR

This paper presents a scalable, site-selective method for synthesizing high-quality Ni-filled multiwalled carbon nanotubes using Ni(salen) as a catalyst, with detailed analysis of their structure and magnetic properties.

Contribution

It introduces a novel photolithographic technique for site-selective growth of Ni-filled nanotubes with detailed characterization.

Findings

Nanotubes grow via tip growth mechanism.

Nanotubes exhibit ferromagnetic behavior with large coercivity.

High-quality Ni filling confirmed by Raman spectroscopy.

Abstract

The synthesis of Ni filled multiwalled carbon nanotubes was performed by atmospheric pressure chemical vapor deposition with propane on Si at 850 C using a simple mixture of Ni(salen), and a conventional photoresist. Analysis of the carbon nanotubes using scanning electron microscopy together with high resolution transmission electron microscopy show that the nanotubes have grown by a tip growth mechanism and exhibit a multi walled structure with partial Ni filling. The high quality of the Ni filled nanotubes is evidenced by Raman spectroscopy. The magnetic properties of Ni filled nanotubes were analyzed using a superconducting quantum interference device which revealed their ferromagnetic behavior with large coercivity. A scalable as well as site selective growth of high quality Ni filled carbon nanotubes is achieved by a simple photolithographic method.