Self-organized growth of bamboo-like carbon nanotube arrays for field emission properties

Balaji Padya,M Ravi,P K Jain,G Padmanabham,K S Bhat,Dipankar Kalita

doi:10.1007/s13204-012-0102-z

Abstract

Well-aligned nitrogen-doped carbon nanotube (N-CNTs) film was fabricated on silicon substrate by thermal chemical vapor deposition process with varying the growth temperature. The effect of growth temperature on morphology, microstructure and crystallinity for the growth of N-CNTs was studied. At all growth temperatures, the bamboo-like morphology of graphene layers with compartments in CNTs were observed in transmission electron microscope micrographs. The doping level and the type of nitrogen-related moieties were determined by X-ray photoelectron spectroscopy analysis. The compartment distance decreases with increase in nitrogen doping level in hexagonal graphite network. The increase in nitrogen doping level in N-CNTs will lead to decrease in crystallinity and in-plane crystallite size. Field emission study of nitrogen-doped carbon nanotubes grown at optimum parameters showed that they are good emitters with a turn-on and threshold field of 0.3 and 1.6 V/μm, respectively. The maximum current density was observed to be 18.8 mA/cm2 at the electric field of 2.1 V/μm. It is considered that the enhanced field emission performance of doped nanotube is due to the presence of lone pairs of electrons on nitrogen atom that supplies more electrons to the conduction band.

Highlights

Miniaturization of nano-scale devices forced researchers to discover advanced materials with unique bulk and surface properties
This paper mainly focused on feasible process to develop the organized growth of highly aligned N-Carbon nanotube (CNT)
nitrogen-doped carbon nanotubes (N-CNTs) arrays grown at the growth temperature 850 °C are well aligned having the length up to 50 lm

Summary

Introduction

Miniaturization of nano-scale devices forced researchers to discover advanced materials with unique bulk and surface properties. Compared to pristine CNTs, the synthesis of nitrogen-doped carbon nanotubes (N-CNTs) have gained growing interest to tailor the electronic (Terrones et al 2002; Ghosh et al 2010; Lim et al 2006), electrical (Ibrahim et al 2010) and mechanical properties (Ganesan et al 2010) with the controlled process parameters aid. In wide range of applications of CNTs, field emission is of paramount interest in which electrons are emitted from a solid material by quantum mechanical tunneling when electric field is applied in high vacuum. The field emission property of the material is dependent on electronic properties. The electronic property of the N-CNTs depends on the dopant concentration and it is a relatively facile method to tune this property by changing the dopant concentration into the bulk material

Methods

Results

Conclusion