Bamboo-shaped aligned CNx nanotubes synthesized using single feedstock at different temperatures and study of their field electron emission

Abstract

The present investigation deals with the synthesis of N-doped aligned bamboo-shaped carbon nanotubes (CNx) by chemical vapour deposition of monoethanolamine/ferrocene mixture on quartz substrate over the temperature range 700–900 °C. All nanotubes exhibited bamboo-like morphology with transverse carbon bridges forming compartments in this temperature range. The concentration of nitrogen content has been controlled in the range 4.8–5.8 at% by controlling the deposition temperature. Scanning electron microscopy, transmission electron microscopy (TEM)/high-resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and thermogravimetric analysis were used to characterize the composition and structural analysis of the as-grown nanotubes. HRTEM revealed that nanotubes prepared at high temperature with low nitrogen content have high graphitization degree. XPS analysis indicated that N 1s signal was split into three peaks. The decomposition of monoethanolamine at reaction temperature produces ammonia which may provide an efficient route of higher nitrogen content on carbon nanotubes. Field emission measurements indicated that N-doped carbon nanotubes prepared at 800 °C showed nice field emission performance with turn-on and threshold field of 1.6 and 2.3 V µm−1, respectively.