Visible to the public The Role of Lateral Confinement in the Localized Heating of Thermionic Emitters Based on Carbon Nanotube Forests

TitleThe Role of Lateral Confinement in the Localized Heating of Thermionic Emitters Based on Carbon Nanotube Forests
Publication TypeConference Paper
Year of Publication2018
AuthorsChowdhury, Mokter M., Fan, Harrison D. E., Chang, Mike, Dridi, Kais, Voon, Kevin, Sawatzky, George A., Nojeh, Alireza
Conference Name2018 31st International Vacuum Nanoelectronics Conference (IVNC)
ISBN Number978-1-5386-5717-1
Keywordsanisotropic structure, C, carbon nanotube forest, carbon nanotube forests, carbon nanotubes, composability, confinement, cyber-physical system, Cyber-physical systems, electrical conduction, Forestry, heat trap effect, laser beam effects, Laser beams, lateral heat confinement, localized hot region, Measurement by laser beam, optical heating, Power lasers, privacy, pubcrawl, resilience, Resiliency, Resistance heating, rotating elliptical laser beam, thermal anisotropicity, thermal conductivity, thermionic electron emission, thermionic electron emitter, thermionic emission, thermionic emitters, thermoelectricity, thermoelectrics, vacuum nanoelectronics, vacuum thermionics, vertically aligned carbon nanotube arrays

When vertically aligned carbon nanotube arrays (CNT forests) are heated by optical, electrical, or any other means, heat confinement in the lateral directions (i.e. perpendicular to the CNTs' axes), which stems from the anisotropic structure of the forest, is expected to play an important role. It has been found that, in spite of being primarily conductive along the CNTs' axes, focusing a laser beam on the sidewall of a CNT forest can lead to a highly localized hot region-an effect known as ``Heat Trap''-and efficient thermionic emission. This unusual heat confinement phenomenon has applications where the spread of heat has to be minimized, but electrical conduction is required, notably in energy conversion (e.g. vacuum thermionics and thermoelectrics). However, despite its strong scientific and practical importance, the existence and role of the lateral heat confinement in the Heat Trap effect have so far been elusive. In this work, for the first time, by using a rotating elliptical laser beam, we directly observe the existence of this lateral heat confinement and its corresponding effects on the unusual temperature rise during the Heat Trap effect.

Citation Keychowdhury_role_2018