Formation of isolated carbon nanofibers with hot-wire CVD using nanosphere lithography as catalyst patterning technique

Abstract

a b s t r a c t a r t i c l e i n f o Available online xxxx Keywords:Hot-wire CVD Carbon nanotubes Nanosphere lithographyRecently the site-density control of carbon nanotubes (CNTs) has attracted much attention as this has become critical for its many applications. To obtain an ordered array of catalyst nanoparticles with good monodispersity nanosphere lithography (NSL) is used. These nanoparticles are tested as catalyst sites in hotwire chemical vapor deposition (HWCVD) of carbon nanostructures. Aside from using NSL also nickel (Ni) nano-islands are made by thermal annealing of a thin Ni film and tested as catalyst sites. Multiwall CNTs, isolated carbon nanofibres, and other nanostructures have been deposited using HWCVD. Tungsten filaments held at~2000°C are used to decompose a mixture of ammonia, methane and hydrogen. The structures have been characterized with Scanning Electron Microscopy, High Resolution Transmission Electron Microscopy, Raman spectroscopy and Rutherford Backscattering Spectroscopy.Crown

Synthesis of carbon nanofibres from waste chicken fat for field electron emission applications

“…This result was in contrast to the typical 9-11 nm L a value for crystalline CNFs obtained using the catalytic CVD method [16,22]. The small L a value found in the present study confirms the amorphous nature of the sample.…”

“…L a is calculated using the Knight formula: L a (nm) = C (I D /I G ) -1 , where the coefficient C = 44 Å is only applicable for λ L = 514 nm [22]. The degree of graphitisation is higher for the larger value of L a [16].…”

Hetero- and homogeneous three-dimensional hierarchical tungsten oxide nanostructures by hot-wire chemical vapor deposition

“…The deposition through a colloidal mask results in an array of prism-like particles in a honeycomb lattice; the method is called nanosphere lithography. This approach is similar to that reported by Micheletto et al [41] and has been used and described by the authors previously [29]. After removal of the colloids through sonication, Ni prisms of a lateral size of a = 335 ± 20 nm and a height of 2.4 ± 0.2 nm reside.…”

Effect of ammonia on Ta filaments in the hot wire CVD process

“…For this research 99.9% pure Ta filaments with a diameter of 0.30 mm are placed in two reactors: the PASTA [12] and the CANTOR [13]. The evolution of the wire resistance during deposition was monitored by keeping the current through the wires constant (within 1%) and measuring the voltage by a Keithley 2000 multimeter.…”

“…Fig. 4 (a) shows an optical micrograph of a filament exposed to a mixed NH 3 , methane (CH 4 ), and H 2 atmosphere as used for CNT deposition [13]. After the deposition, the filaments were golden in colour and highly brittle.…”