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

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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.

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The electron emission model of CNT arrays under the high-voltage pulse electric field.
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Figure 5: The electron emission model of CNT arrays under the high-voltage pulse electric field.

Mentions: A tube configuration of CNTs enables them to absorb gas, and the dense CNTs can adsorb a large amount of gas molecules [22,23]. The CNTs can emit high-intensity electron beams under the high-voltage pulse electric field. Under the effect of the high-intensity electron beams, the adsorbent gas molecules are easy to become ionization [8-10,23]. The CCD camera has captured the light emission from the CNT arrays. This demonstrates that plasmas formed on the array surface during the emission process. The electron emissions of CNT arrays under the pulse electric field are not pure field emission. The production mechanism of the high-intensity electron beams from the CNT arrays is plasma-induced emission. The emission model of the CNT arrays under the high-voltage pulse electric field is shown in Figure 5. Above all, the plasma layer forms on the cathode surface under the effect of high-intensity electron beams. Subsequently, the cathode surface is covered by plasma, and the electron beams are extracted from the surface plasma. The results demonstrate that the CNT arrays have the ability of emitting high-intensity electron beams under the pulse electric field. The CNT array cathodes are expected to be applied to high-power vacuum electronic devices as electron beam sources.


Investigation on the Plasma-Induced Emission Properties of Large Area Carbon Nanotube Array Cathodes with Different Morphologies
The electron emission model of CNT arrays under the high-voltage pulse electric field.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: The electron emission model of CNT arrays under the high-voltage pulse electric field.
Mentions: A tube configuration of CNTs enables them to absorb gas, and the dense CNTs can adsorb a large amount of gas molecules [22,23]. The CNTs can emit high-intensity electron beams under the high-voltage pulse electric field. Under the effect of the high-intensity electron beams, the adsorbent gas molecules are easy to become ionization [8-10,23]. The CCD camera has captured the light emission from the CNT arrays. This demonstrates that plasmas formed on the array surface during the emission process. The electron emissions of CNT arrays under the pulse electric field are not pure field emission. The production mechanism of the high-intensity electron beams from the CNT arrays is plasma-induced emission. The emission model of the CNT arrays under the high-voltage pulse electric field is shown in Figure 5. Above all, the plasma layer forms on the cathode surface under the effect of high-intensity electron beams. Subsequently, the cathode surface is covered by plasma, and the electron beams are extracted from the surface plasma. The results demonstrate that the CNT arrays have the ability of emitting high-intensity electron beams under the pulse electric field. The CNT array cathodes are expected to be applied to high-power vacuum electronic devices as electron beam sources.

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.