Thermionic cooling occurs when energetic hot electrons emit from the cathode surface, thus carry energy away and cool the cathode. Because of the high thermionic emission from functionalized CNTs surface, significant cooling effect has been achieved – temperature drop as much as 81 degree has been observed on the CNT thin film emitter surface. This has the potential for thermionic cooler of microelectronics/ power electronics devices.
Examples of cooling effect
Temperature Profiles
The temperature profiles of the cathode measured using a pyrometer provide details of energy balance of the cathode and enable the calculation of the cooling efficiency.
The temperature profiles of the cathode measured using a pyrometer provide details of energy balance of the cathode and enable the calculation of the cooling efficiency.
Cooling Efficiency
The cooling efficiency in this study is defined as the ratio of cooling power to total input power or cooling power as a percentage of total input power to the cathode surface.
The cooling efficiency in this study is defined as the ratio of cooling power to total input power or cooling power as a percentage of total input power to the cathode surface.
References:
Feng Jin and Allyn Beaver, Barium strontium oxide functionalized carbon nanotubes thin film thermionic emitter with superior thermionic emission capability, Journal of Vacuum Science & Technology B: 35, 041202 (2017)
Feng Jin & Scott Little, “Thermionic cooling with functionalized carbon nanotube thin films”, Appl. Phys. Lett. 106, 113102 (2015).
Feng Jin and Scott Little, “Degradation of Mechanical Strength of Vertically Aligned Carbon Nanotubes at Growth Interface Joints at High Temperatures,” Proc. MRS 1137-EE05-09 (February, 2009).
F. Jin, Y. Liu, C. M. Day, S. Little, "Enhanced field emission from carbon nanotubes with a thin layer of low work function barium strontium oxide surface coating," published in Journal of Vacuum Science & Technology B 25, 1785 (2007)
Feng Jin, Yan Liu, Christopher Day and Scott Little, “Enhanced electron emission from functionalized carbon nanotubes with a barium strontium oxide coating produced by magnetron sputtering,” Carbon, Mar 2007, Vol. 45 Issue 3, p587-593.
Feng Jin, Yan Liu and Christopher Day, “Barium strontium oxide coated carbon nanotubes as field emitters,” Applied Physics Letters, April, 2007, Vol. 90 Issue 14.
F. Jin, Y. Liu, S. Little, C. M. Day, “A new thermionic cathode based on carbon nanotubes with a thin layer of low work function barium strontium oxide surface coating,” Proceedings of the 11th International Symposium on the Science and Technology of Light Sources, May, 2007.
Yan Liu and Christopher Day, Scott Little and Feng Jin, “Thin film deposition of barium strontium oxide by rf magnetron sputtering,” Journal of Vacuum Science & Technology A 24(6), Nov/Dec 2006.
Feng Jin, Yan Liu and Christopher Day, “Thermionic Emission from Carbon Nanotubes with a Thin Layer of Low Work Function Barium Strontium Oxide Surface Coating,” Applied Physics Letters, 88, 163116 (2006).