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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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a The waveforms of diode voltage and emission currents from the four kinds of array cathodes with different CNT heights. b Dependence of the cathode current on the number of pulses.
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Figure 3: a The waveforms of diode voltage and emission currents from the four kinds of array cathodes with different CNT heights. b Dependence of the cathode current on the number of pulses.

Mentions: An application of the pulse electric field caused the appearance of an intense current electron emission from the CNT array cathodes. Figure 3 gives the emission current waveforms and the emission stability curves from the four kinds of array cathodes with different CNT heights. During one double-pulse, the highest voltages of two pulses are about 0.75 and 0.58 MV, respectively. Under the same diode voltage, the emission current waveforms of four kinds of array cathodes have same characteristics. The emission currents have big differences between the first pulse and the second pulse. The big difference of emission currents attributes to the formation and expansion of the surface plasma [8-10]. For the four kinds of arrays with different CNT heights of 4, 7, 14 and 16 μm, the highest emission currents are 3474, 2115, 2056 and 1073 A, respectively. The CNT arrays of four kinds of cathodes have different ratios of CNT height to CNT-to-CNT distance. The difference in the emission currents of the CNT arrays can be caused by only the ratios of CNT height to CNT-to-CNT distance. With increase in the ratios of CNT height to CNT-to-CNT distance, the emission currents decrease gradually. The 4-μm height CNT array has the highest emission current among the four kinds of CNT arrays. The average electric field of the second pulse is about 6 V/μm, and the corresponding highest emission current density of 4-μm height CNT array is about 170–180 A/cm2. The relationship between the emission currents and the number of pulses for the four kinds of arrays is presented in Figure 3b. Along with the continuance of the pulse emission, the CNT arrays would lose the emission ability gradually [13-15]. The results show that after 80 pulses, the emission currents of the four kinds of CNT array have about from 11.3 to 12.9% reductions.


Investigation on the Plasma-Induced Emission Properties of Large Area Carbon Nanotube Array Cathodes with Different Morphologies
a The waveforms of diode voltage and emission currents from the four kinds of array cathodes with different CNT heights. b Dependence of the cathode current on the number of pulses.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: a The waveforms of diode voltage and emission currents from the four kinds of array cathodes with different CNT heights. b Dependence of the cathode current on the number of pulses.
Mentions: An application of the pulse electric field caused the appearance of an intense current electron emission from the CNT array cathodes. Figure 3 gives the emission current waveforms and the emission stability curves from the four kinds of array cathodes with different CNT heights. During one double-pulse, the highest voltages of two pulses are about 0.75 and 0.58 MV, respectively. Under the same diode voltage, the emission current waveforms of four kinds of array cathodes have same characteristics. The emission currents have big differences between the first pulse and the second pulse. The big difference of emission currents attributes to the formation and expansion of the surface plasma [8-10]. For the four kinds of arrays with different CNT heights of 4, 7, 14 and 16 μm, the highest emission currents are 3474, 2115, 2056 and 1073 A, respectively. The CNT arrays of four kinds of cathodes have different ratios of CNT height to CNT-to-CNT distance. The difference in the emission currents of the CNT arrays can be caused by only the ratios of CNT height to CNT-to-CNT distance. With increase in the ratios of CNT height to CNT-to-CNT distance, the emission currents decrease gradually. The 4-μm height CNT array has the highest emission current among the four kinds of CNT arrays. The average electric field of the second pulse is about 6 V/μm, and the corresponding highest emission current density of 4-μm height CNT array is about 170–180 A/cm2. The relationship between the emission currents and the number of pulses for the four kinds of arrays is presented in Figure 3b. Along with the continuance of the pulse emission, the CNT arrays would lose the emission ability gradually [13-15]. The results show that after 80 pulses, the emission currents of the four kinds of CNT array have about from 11.3 to 12.9% reductions.

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.


Related in: MedlinePlus