Electron field emission from magnetic nanomaterial encapsulated multi-walled carbon nanotubes
Applied Physics A
(Impact Factor: 1.7).
01/2010; 98(1):195-202. DOI: 10.1007/s00339-009-5373-1
The present work describes the field emission characteristics of nanoscale magnetic nanomaterial encapsulated multi-walled
carbon nanotubes (MWNTs) fabricated over flexible graphitized carbon cloth. Ni/MWNTs, NiFe/MWNTs and NiFeCo/MWNTs have been
synthesized by catalytic chemical vapor decomposition of methane over Mischmetal (Mm)-based AB3 (MmNi3, MmFe1.5Ni1.5 and MmFeCoNi) alloy hydride catalysts. Metal-encapsulated MWNTs exhibited superior field emission performance than pure MWNT-based
field emitters over the same substrate. The results indicate that a Ni-filled MWNT field emitter is a promising material for
practical field emission application with a lowest turn-on field of 0.6V/μm and a high emission current density of 0.3mA/cm2 at 0.9V/μm.
Available from: Raghavan Baby Rakhi
Available from: Junpeng Lu
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ABSTRACT: Quasi-1D α-Fe2O3 nanostructure arrays of four different morphologies (random nanoflakes, random nanobelts, quasi-aligned nanostrips and quasi-aligned nanoneedles) were successfully synthesized via a simple heating process. Field emission measurements indicate that the α-Fe2O3 nanoneedle arrays are superior field emitter exhibiting low turn-on voltage, high current density, and large field-enhancement factor due to better vertical alignment and higher aspect ratio. In addition, we found that adsorbed oxygen molecules greatly hindered the field emission performance of the nanostructures. Prolonged field emission process could drive the oxygen molecules away and give rise to markedly improved and efficient α-Fe2O3 nanostructures field emitter. The improved field emission is attributed to desorption of the oxygen molecules during the field emission process.
Available from: 184.108.40.206
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ABSTRACT: Attempts to dope carbon nanotube (CNT) with impurities in order to control the electronic properties of the CNT is a natural course of action. Boron is known to improve both the structural and electronic properties. In this report, we study the field emission properties of Boron-doped double-walled CNT (DWCNT). Boron-doped DWCNT films were fabricated by catalytic decomposition of tetrahydrofuran and triisopropyl borate over a Fe-Mo/MgO catalyst at 900 o C. We measured the field emission current by varying the doping amount of Boron from 0.8 to 1.8 wt%. As the amount of doped boron in the DWCNT increases, the turn-on-field of the DWCNT decreases drastically from 6 V/µm to 2 V/µm. The current density of undoped CNT is 0.6 mA/cm 2 at 9 V, but a doped-DWCNT sample with 1.8 wt% achieved the same current density only at only 3.8 V. This shows that boron doped DWCNTs are potentially useful in low voltage operative field emitting device such as large area flat panel displays.
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