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Multiscale Model of Heat Dissipation Mechanisms During Field Emission from Carbon Nanotube Fibers

Zhu, Weiming
http://orcid.org/0000-0002-9607-3217
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530880336075941

Abstract Details

2018, PhD, University of Cincinnati, Engineering and Applied Science: Electrical Engineering.
A multiscale model of field emission (FE) from a carbon nanotube fiber (CNF) is developed which takes into account Joule heating within the fiber and radiative cooling and the energy exchange mechanism at the tip of the individual carbon nanotubes (CNTs ) in the array located at the fiber apex. The model predicts the fraction of CNTs being destroyed as a function of the applied external electric field and reproduces many experimental features observed in some recently investigated CNFs such as, order of magnitude of the emission current (mA range), low turn on electric field (fraction of V/µm), deviation from pure Fowler-Nordheim behavior at large applied electric field, hysteresis of the FE characteristics, and a spatial variation of the temperature along the CNF axis with a maximum close to its tip of a few hundred degree Celsius. The multiscale model is in qualitative agreement with the FE characteristics of CNFs measured by collaborators at Wright-Patterson Air Force Base (WPAFB). The model is used to predict the FE characteristics of both linear and hexagonal arrays of seven CNFs taking into account the effects of electrostatic shielding between adjacent CNFs. The multiscale model described in this dissertation can provide a tool to develop cold cathodes that can provide a current density of a few times 10^5 A/m^2 and a total current of at least 10 mA for at least several hundred hours of continuous waveform (CW) operation, when operated at temperature less than 1000 degree Celsius.
Marc Cahay, Ph.D. (Committee Chair)
Je-Hyeong Bahk, Ph.D. (Committee Member)
Punit Boolchand, Ph.D. (Committee Member)
Rashmi Jha, Ph.D. (Committee Member)
Hans Peter Wagner, Ph.D. (Committee Member)
161 p.
Electrical Engineering
Carbon Nanotube Fibers; Field Emission; Multiscale Model; Numerical Simulation; Heat Dissipation Mechanism

Recommended Citations

Citations

  • Zhu, W. (2018). Multiscale Model of Heat Dissipation Mechanisms During Field Emission from Carbon Nanotube Fibers [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530880336075941

    APA Style (7th edition)

  • Zhu, Weiming. Multiscale Model of Heat Dissipation Mechanisms During Field Emission from Carbon Nanotube Fibers. 2018. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530880336075941.

    MLA Style (8th edition)

  • Zhu, Weiming. "Multiscale Model of Heat Dissipation Mechanisms During Field Emission from Carbon Nanotube Fibers." Doctoral dissertation, University of Cincinnati, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530880336075941

    Chicago Manual of Style (17th edition)

ucin1530880336075941
388
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This open access ETD is published by University of Cincinnati and OhioLINK.