Limits...
Investigation on the Plasma-Induced Emission Properties of Large Area Carbon Nanotube Array Cathodes with Different Morphologies

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Large area well-aligned carbon nanotube (CNT) arrays with different morphologies were synthesized by using a chemical vapor deposition. The plasma-induced emission properties of CNT array cathodes with different morphologies were investigated. The ratio of CNT height to CNT-to-CNT distance has considerable effects on their plasma-induced emission properties. As the ratio increases, emission currents of CNT array cathodes decrease due to screening effects. Under the pulse electric field of about 6 V/μm, high-intensity electron beams of 170–180 A/cm2 were emitted from the surface plasma. The production mechanism of the high-intensity electron beams emitted from the CNT arrays was plasma-induced emission. Moreover, the distribution of the electron beams was in situ characterized by the light emission from the surface plasma.

No MeSH data available.


Morphologies and structures of CNT arrays: a The assembled CNT array cathode on a copper stage, b The CCD image of the CNT array cathodes that are not emit, c Low-resolution TEM image of the CNTs, d High-resolution TEM image of the CNTs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211494&req=5

Figure 1: Morphologies and structures of CNT arrays: a The assembled CNT array cathode on a copper stage, b The CCD image of the CNT array cathodes that are not emit, c Low-resolution TEM image of the CNTs, d High-resolution TEM image of the CNTs.

Mentions: The assembled CNT array cathode is shown in Figure 1a. The black disk inside the exterior ring is the CNT array film. The emission surface of the array cathode is a disk with 50 mm in diameter. As a whole, the CNT arrays are distribute uniformly on the silicon substrate. Figure 1b shows the CCD image of the cathodes that are not emit, and the middle ellipse of the image is the cathode surface. The only different growth condition among the four kinds of CNT arrays is the growth time, and the CNTs of the four samples have similar diameters. The low-resolution TEM micrograph of the CNTs is shown in Figure 1c, which shows that the CNTs are held together by van der Waals interactions and the CNTs form tight bundles. The diameter of the nanotubes is about 10 nm based on the high-resolution TEM image (shown in the Figure 1d). The high-resolution TEM image reveals that the CNTs are multi-walled. The multi-walled CNTs are relatively clean, and the walls have low defect density.


Investigation on the Plasma-Induced Emission Properties of Large Area Carbon Nanotube Array Cathodes with Different Morphologies
Morphologies and structures of CNT arrays: a The assembled CNT array cathode on a copper stage, b The CCD image of the CNT array cathodes that are not emit, c Low-resolution TEM image of the CNTs, d High-resolution TEM image of the CNTs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211494&req=5

Figure 1: Morphologies and structures of CNT arrays: a The assembled CNT array cathode on a copper stage, b The CCD image of the CNT array cathodes that are not emit, c Low-resolution TEM image of the CNTs, d High-resolution TEM image of the CNTs.
Mentions: The assembled CNT array cathode is shown in Figure 1a. The black disk inside the exterior ring is the CNT array film. The emission surface of the array cathode is a disk with 50 mm in diameter. As a whole, the CNT arrays are distribute uniformly on the silicon substrate. Figure 1b shows the CCD image of the cathodes that are not emit, and the middle ellipse of the image is the cathode surface. The only different growth condition among the four kinds of CNT arrays is the growth time, and the CNTs of the four samples have similar diameters. The low-resolution TEM micrograph of the CNTs is shown in Figure 1c, which shows that the CNTs are held together by van der Waals interactions and the CNTs form tight bundles. The diameter of the nanotubes is about 10 nm based on the high-resolution TEM image (shown in the Figure 1d). The high-resolution TEM image reveals that the CNTs are multi-walled. The multi-walled CNTs are relatively clean, and the walls have low defect density.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Large area well-aligned carbon nanotube (CNT) arrays with different morphologies were synthesized by using a chemical vapor deposition. The plasma-induced emission properties of CNT array cathodes with different morphologies were investigated. The ratio of CNT height to CNT-to-CNT distance has considerable effects on their plasma-induced emission properties. As the ratio increases, emission currents of CNT array cathodes decrease due to screening effects. Under the pulse electric field of about 6 V/μm, high-intensity electron beams of 170–180 A/cm2 were emitted from the surface plasma. The production mechanism of the high-intensity electron beams emitted from the CNT arrays was plasma-induced emission. Moreover, the distribution of the electron beams was in situ characterized by the light emission from the surface plasma.

No MeSH data available.