Characterization of carbon nanotube field emitters in pulsed operation mode

Daniela Leberl; Raghunandan Ummethala; Albrecht Leonhardt; Bernhard Hensel; Sandro F. Tedde; Oliver Schmidt; Oliver Hayden

doi:10.1116/1.4773058

Characterization of carbon nanotube field emitters in pulsed operation mode

Daniela Leberl, Raghunandan Ummethala, Albrecht Leonhardt, Bernhard Hensel, Sandro F. Tedde, Oliver Schmidt, Oliver Hayden

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20 Scopus citations

Abstract

Carbon nanotubes (CNTs) are promising candidates as electron sources for novel x-ray tubes. Short pulses, high emission currents, and long-term stability are prerequisites for practical applications in medical x-ray imaging. Here, the authors present field emission from CNTs in pulsed operation mode exhibiting very high stability for 200 cumulative hours and a maximum current of 126 mA corresponding to 202 mA/cm² at an applied field of 9.3 V/μm. They investigated the correlation of classical emitter characteristics such as threshold field and field enhancement factor to the long-term stability and maximum emission current. This correlation was found to be rather poor. Instead, they observed a steady voltage increase for a fixed current during lifetime experiments. This observation allowed to derive a degradation parameter which determines the emitter quality for pulsed applications. Detailed investigations of the degradation in dependency of pressure, duty cycle, and pulse-on time were performed to predict the stability and lifetime of CNT-based field emitters.

Original language	English
Article number	012204
Journal	Journal of Vacuum Science and Technology B
Volume	31
Issue number	1
DOIs	https://doi.org/10.1116/1.4773058
State	Published - Jan 2013
Externally published	Yes

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title = "Characterization of carbon nanotube field emitters in pulsed operation mode",

abstract = "Carbon nanotubes (CNTs) are promising candidates as electron sources for novel x-ray tubes. Short pulses, high emission currents, and long-term stability are prerequisites for practical applications in medical x-ray imaging. Here, the authors present field emission from CNTs in pulsed operation mode exhibiting very high stability for 200 cumulative hours and a maximum current of 126 mA corresponding to 202 mA/cm2 at an applied field of 9.3 V/μm. They investigated the correlation of classical emitter characteristics such as threshold field and field enhancement factor to the long-term stability and maximum emission current. This correlation was found to be rather poor. Instead, they observed a steady voltage increase for a fixed current during lifetime experiments. This observation allowed to derive a degradation parameter which determines the emitter quality for pulsed applications. Detailed investigations of the degradation in dependency of pressure, duty cycle, and pulse-on time were performed to predict the stability and lifetime of CNT-based field emitters.",

author = "Daniela Leberl and Raghunandan Ummethala and Albrecht Leonhardt and Bernhard Hensel and Tedde, {Sandro F.} and Oliver Schmidt and Oliver Hayden",

note = "Funding Information: This research was funded by the German Federal Ministry of Education and Research (BMBF, CarboFEM 03X0201A). The authors thank Dr. Wolfram Knapp at the University of Magdeburg and Mr. Ernst Neumeier, Dr. Christian Riedl, and Mr. Andreas Boehme at Siemens Healthcare for valuable discussions.",

year = "2013",

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doi = "10.1116/1.4773058",

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T1 - Characterization of carbon nanotube field emitters in pulsed operation mode

AU - Leberl, Daniela

AU - Ummethala, Raghunandan

AU - Leonhardt, Albrecht

AU - Hensel, Bernhard

AU - Tedde, Sandro F.

AU - Schmidt, Oliver

AU - Hayden, Oliver

N1 - Funding Information: This research was funded by the German Federal Ministry of Education and Research (BMBF, CarboFEM 03X0201A). The authors thank Dr. Wolfram Knapp at the University of Magdeburg and Mr. Ernst Neumeier, Dr. Christian Riedl, and Mr. Andreas Boehme at Siemens Healthcare for valuable discussions.

PY - 2013/1

Y1 - 2013/1

N2 - Carbon nanotubes (CNTs) are promising candidates as electron sources for novel x-ray tubes. Short pulses, high emission currents, and long-term stability are prerequisites for practical applications in medical x-ray imaging. Here, the authors present field emission from CNTs in pulsed operation mode exhibiting very high stability for 200 cumulative hours and a maximum current of 126 mA corresponding to 202 mA/cm2 at an applied field of 9.3 V/μm. They investigated the correlation of classical emitter characteristics such as threshold field and field enhancement factor to the long-term stability and maximum emission current. This correlation was found to be rather poor. Instead, they observed a steady voltage increase for a fixed current during lifetime experiments. This observation allowed to derive a degradation parameter which determines the emitter quality for pulsed applications. Detailed investigations of the degradation in dependency of pressure, duty cycle, and pulse-on time were performed to predict the stability and lifetime of CNT-based field emitters.

AB - Carbon nanotubes (CNTs) are promising candidates as electron sources for novel x-ray tubes. Short pulses, high emission currents, and long-term stability are prerequisites for practical applications in medical x-ray imaging. Here, the authors present field emission from CNTs in pulsed operation mode exhibiting very high stability for 200 cumulative hours and a maximum current of 126 mA corresponding to 202 mA/cm2 at an applied field of 9.3 V/μm. They investigated the correlation of classical emitter characteristics such as threshold field and field enhancement factor to the long-term stability and maximum emission current. This correlation was found to be rather poor. Instead, they observed a steady voltage increase for a fixed current during lifetime experiments. This observation allowed to derive a degradation parameter which determines the emitter quality for pulsed applications. Detailed investigations of the degradation in dependency of pressure, duty cycle, and pulse-on time were performed to predict the stability and lifetime of CNT-based field emitters.

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Characterization of carbon nanotube field emitters in pulsed operation mode

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