Effect of surface morphology of Ni thin film on the growth of aligned carbon nanotubes by microwave plasma-enhanced chemical vapor deposition

Abstract

Aligned carbon nanotubes were synthesized on Ni-coated Si substrates using microwave plasma-enhanced chemical vapor deposition. The surface morphology of Ni thin films was varied with the rf power density during the rf magnetron sputtering process. It was found that the growth of carbon nanotubes was strongly influenced by the surface morphology of Ni thin film. Pure carbon nanotubes were synthesized on Ni thin film with uniformly distributed grain sizes, whereas large amounts of carbonaceous particles were produced in addition to the nanotubes, when the nanotubes were grown on Ni thin film with widely distributed grain sizes. With decreasing Ni-grain size, the diameter of nanotubes decreased and the length increased. High-resolution transmission electron microscope images clearly demonstrated the nanotubes to be multiwalled, and the graphitized structures were confirmed from the Raman spectra. Efficient field emission was observed from the diode structure with the nanotube tips.

Field Emission from Lateral Multiwalled Carbon Nanotube Yarn Emitters

“…These values indicate lower turn-on electric fields than those of the vertical emitters. The lateral emitter shows a same gap dependence of field emission properties as the conventional vertical emitters (Choi et al, 2000;Moon et al, 2006;Chen et al, 2009).…”

Robust and High Current Cold Electron Source Based on Carbon Nanotube Field Emitters and Electron Multiplier Microchannel Plate

“…Where (nm) = nanotube diameter, Where d is inter electrode distance The calculated value of field enhancement factor was ~9300, which implies that E l where nanotubes are emitting electrons is ~9300 times stronger than E m . Value of β obtained in this work is much higher than previously reported for MWNTs, ranging from 1000 to 5000 [98][99][100].The previously reported diameters of MWNTs were in the range of 20-50 nm, therefore the higher value obtained in this study can be attributed to the structure of the nanotubes which have a smaller diameter (~10 nm) and higher aspect ratio (~1500). by using Bravais-Friedel-Donnay-Harker (BFDH) law, which states that growth rate of a crystal is inversely proportional to the inter-planar spacing of that face, which is the short axis i.e.…”

Carbon Oxidation Reaction over Pt/Spherical Alumina Beads Catalysts Prepared by Sputtering Method

“…The sputter deposition method was widely used to fabricate thin film such as Pt [1], Au [2], and Ni [3] films on substrate. Recently, sputter deposition method was explored as an approach to the preparation of heterogeneous catalysts.…”