Decomposition Of Methane Gas Research Articles

Fabrication of Carbon Nanoparticle Strand under Pulsed Arc Discharge

Nowadays, carbon-based nanomaterial application on nanoelectronic is growing fast. Therefore, the nanoparticle fabrication as a device, needs to be optimized. In the present work, a pulsed AC arc discharge apparatus is fabricated for production of carbon nanoparticles (CNPs)-based device, which is derived from decomposition of methane gas in plasma condition and atmospheric pressure controlled by a bobbling system. The morphological properties and identification of synthesized CNPs are characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and nanofocus techniques. The analysis of obtained images confirms the existence of CNPs (mainly carbon nanotubes CNTs) in this method. Also, pulsed electric field equation and relation between growth time and distance between two electrodes are investigated. Moreover, growth conditions of CNPs and their physical mechanism are discussed. Finally, the current-voltage (I-V) characteristics of synthesized CNPs are examined.

Influence of raw powder size, reaction temperature, and soaking time on synthesis of SiC/SiO2 coaxial nanowires via thermal evaporation

High-yield SiC/SiO2 core-shell nanowires were synthesized without adding metal catalysts from outside through a simple thermal evaporation of silicon powders during decomposition of methane gas. The influence of three parameters, size of Si raw powder (50 nm and 5 μm), reaction temperature (1573, 1623 and 1673 K), and soaking time (1, 3 and 6 h), was investigated. The typical synthesized nanowires from different conditions possess the diameter of no thicker than 100 nm with several tens micrometers in length. It was addressed that the condition using the smaller size Si powder, which contained the highest amount of oxygen, at higher temperature lead to more complete reaction to obtain a large quantity of nanowires. The synthesized nanowires at higher reaction temperature and longer soaking time possessed larger core than those nanowires prepared at lower reaction temperature and shorter soaking time. Oxidation of larger size Si powder improved yield of nanowires. Based on these results, it was suggested that the typical nanowires should be grown via the oxide-assisted growth mechanism.

Substrate effects on the growth of carbon nanotubes by thermal decomposition of methane

A systematic investigation into the growth of single-walled carbon nanotubes (SWNTs) on thin metallic films deposited on various substrates was performed. Aluminum–iron–molybdenum multi-layer thin films were deposited on various substrates to determine which substrates promote the growth of SWNTs over multi-walled nanotubes (MWNTs) during the decomposition of methane gas. It was determined that the substrate employed as the supporting material for the Fe thin film catalyst has a strong effect on controlling the growth of either SWNTs or MWNTs, with clear trends noticeable. The ideal substrate for SWNT growth was a spun-on alumina film, while, single crystal substrates promoted the growth of mixed SWNTs and MWNTs. All remaining substrates grew primarily MWNTs.

The subimplantation model for diamond-like carbon films deposited by methane gas decomposition

Abstract In this work, the formation of hard a-C:H films deposited on the cathode of an r.f. sputtering system through the decomposition of methane gas was explained using the subimplantation model. Even though in a r.f. plasma deposition the ions striking the films surface are not monoenergetic, the stress data match the theoretical model proposed by C.A. Davis. The stress versus bias plot shows a behavior similar to those already obtained for ta-C and ta-C:H films, which are prepared using monoenergetic ion beam.

A 13C isotopic tracing study of a-C:H thin-film growth

The growth mechanisms of amorphous carbon (a-C:H) thin films obtained by the decomposition of methane gas in a multipolar plasma set up were studied using 13C as a tracer. Hydrogenated carbon films first grown in a methane plasma with natural isotopic composition (12C) were further grown in highly enriched 13C methane discharge (experiments were also carried out with the reverse order). 13C profiles were obtained by resonant nuclear reaction depth profiling using the narrow (FWHM<100 eV) resonance at 1747.6 keV, in the 13C(p, γ)14N nuclear reaction. Plasma conditions were varied so as to vary the energy of particles arriving at the sample surface from 30 eV to 500 eV. In all cases, a system of two layers was observed: a pure 13C film overlaying a pure 12C film (or the reverse order) with a rather sharp interface between the two layers. These results suggest layer by layer amorphous hydrogenated carbon film growth with minimal mixing or interdiffusion of the isotopic layers induced by the ionic bombardment during the growth.