The role of carbon nanotube forest density in thermionic emission

Voon, Kevin; Dridi, Kais; Chowdhury, Mohammed Raihan; Chang, Man Kit; Nojeh, Alireza

doi:10.1109/ivnc.2016.7551493

Cited by 2 publications

(3 citation statements)

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“…The process is performed in the mixture of argon, hydrogen, and ethylene that acts as the carbon-containing active precursor for the growth of the CNT forests at a temperature of 750 °C. More details about the growth process can be found in other reports. , One method to control the height of the CNT forest is to vary the growth time, that is, the time period for which ethylene is flowed through the CVD growth chamber. The growth time chosen for this study is 40 min, which results in CNT forests of 1 mm or greater in height.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…More details about the growth process can be found in other reports. 31,53 One method to control the height of the CNT forest is to vary the growth time, that is, the time period for which ethylene is flowed through the CVD growth chamber. The growth time chosen for this study is 40 min, which results in CNT forests of 1 mm or greater in height.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…In this type of devices, the gap between the cathode (CNT forest in this case) and the anode should be ideally on the order of a few micrometers for efficient collection of the emitted electrons . This has been a challenge in previous studies, which could only use gaps on the order of a millimeter due to the nonuniformity in the CNT forest structures used. − The presence of stray CNT bundles emerging from the top of the forest is also a critical problem as it can cause short circuits with the anode.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Post-Growth Planarization of Vertically Aligned Carbon Nanotube Forests for Electron-Emission Devices

Hassan

Nojeh

Takahata

2019

ACS Appl. Nano Mater.

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This paper reports a microplasma-based planar process for as-grown carbon nanotube (CNT) forests to produce macroscopically flat top surfaces over different scales. This noncontact process is based on microscale removal of CNTs driven by pulsed electrical discharge generated at the interface between the forest surface and a stainless-steel planar electrode, achieving controlled subtractive planarization of the forest structure while maintaining the CNTs’ alignment. Forest samples with large surface areas of up to 26 mm2 with the largest height variations of ∼1 mm are successfully processed to demonstrate improvements by up to ∼60× in the height uniformity of the forests and ∼30× in the parallelism of their top surfaces with the substrate planes. Elemental analyses suggest that the contamination from the electrode material is minor, or negligibly small when the discharge process does not experience short-circuit events that can lead to damaging irregular arcs. The promising results obtained in this work are expected to pave the way for studying the properties of the CNT forest further and promote its application in areas where height uniformity is of prime interest, such as in electron emission devices.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%