Growth of carbon nanotubes through selective deposition of nanoparticles

Abstract

This paper describes the selective growth of a high density of Carbon NanoTubes (CNTs) (up to 2.5 10¹¹ CNT cm⁻²) in nanometric (140 to 300 nm) holes etched in silicon dioxide (vias). The method involves (i) the electrografting of a thin layer of poly(hydroxyethyl methacrylate) (polyHEMA) at the Si bottom of the SiO₂ vias; (ii) independent synthesis of nanometric iron oxide nanoparticles (NP) by the polyol method, the NPs being capped by diethylene glycol (DEG); (iii) HF cleaning of the SiO₂ structure; (iv) selective deposition of the NPs on the polyHEMA layer at the bottom of the vias; (v) burn-off of the polymer; (vi) Chemical Vapour Deposition (CVD) growth of the CNTs. The success of the experiment is based on the fine tuning of the selective interactions between the capping of the NPs and the polymer deposited exclusively at the bottom of the vias.