Nanofabrication by electrochemical routes of Ni-coated ordered arrays of carbon nanotubes

Abstract

Ordered arrays of carbon nanotubes (CNT)\ud have been coated by Ni nanoparticles and Ni thin films\ud by using the chronoamperometry technique for nickel\ud reduction. Two different kinds of nanotube arrays have\ud been used: aligned bundles of CNT grown on Si\ud substrates by chemical vapour deposition (CVD) and\ud networks of CNT bundles positioned via a dielectrophoretic\ud post-synthesis process between the\ud electrodes of a multifinger device. The morphology\ud and structure of the Ni-coated CNT bundles have been\ud characterized by field emission scanning electron\ud microscopy (FE-SEM) and X-ray diffraction (XRD).\ud By changing the parameters of the electrochemical\ud process, it is possible to modulate the morphological\ud characteristics of the Ni deposits, which can be\ud obtained in form of nanoparticles uniformly distributed\ud along the whole length of the CNT bundles or of\ud Ni thin films. A qualitative study of the nucleation and\ud growth mechanism of Ni onto CNT has been performed\ud using the theoretical model for diffusioncontrolled\ud electrocrystallization, and a correlation\ud between growth mechanism and samples morphology\ud is presented and discussed. The possibility to maintain\ud the architecture of the pristine nanotube deposits\ud after the Ni coating process opens new perspectives\ud for integration of CNT/Ni systems in magnetic and\ud spintronics devices

The hexagonal close-packed nickel nanocrystals prepared by fast scan voltammetry

“…As expected, the increasing concentration of H + intensify the hydrogen evolution rate, affecting the hydrodynamic conditions and, hence increasing the limiting diffusion current density of electrode processes [50]. Therefore, the nucleation and growth processes could be dependent of such conditions changes during the electrodeposition [51]. In the case of Ni electrodeposition it has been reported [29] that at pH < 4, continuous nucleation is inhibited.…”

Ni(NiO)/single-walled carbon nanotubes composite: Synthesis of electro-deposition, gas sensing property for NO gas and density functional theory calculation

“…According to the three peaks of the RBM (159, 171, 179 cm À1 ), the scattering peak at 159 cm À1 was attributed to (18, 0) SWCNT having metallic; we related the 171 cm À1 peak to (15,3) SWCNT still with metallic property; and the peak at 179 cm À1 was assigned to (16, 0) SWCNT that is mainly semiconducting. Fig.…”

“…The synthesized SWCTs mainly consisted of three diameter-size SWCNTs: semiconducting (16, 0), metallic (15,3) and metallic (18,0) which were demonstrated by the Raman spectra through the arc discharge method.…”

Transport mechanism in granular Ni deposited on carbon nanotubes fibers

“…13 The controlled decoration of the fibers has been realized by electrochemical routes optimized in previous research. 14 The fibers' diameter is D = 95 μm, their mechanical strength ∼100 MPa, and their room-temperature electrical resistivity ∼4 m cm. These fibers behave as semiconductors at room temperature and below.…”