Abstract
Carbon nanotubes (CNTs) are promising candidates to create new thermionic- and photoemission materials. Intercalation of CNTs with alkali metals, such as potassium, greatly reduces their work functions, and the low electron scattering rates of small-diameter CNTs offer the possibility of efficient photoemission. This work uses a Nd:YAG (YAG denotes yttrium aluminum garnet) laser to irradiate single- and multiwalled CNTs intercalated with potassium, and the resultant energy distributions of photo- and thermionic emitted electrons are measured using a hemispherical electron energy analyzer over a wide range of temperatures. For both single- and multiwalled CNTs intercalated with potassium, the authors observe a temperature dependent work function that has a minimum of approximately 2.0 eV at approximately 600 K. At temperatures above 600 K, the measured work function values increase with temperature presumably due to deintercalation of potassium atoms. Laser illumination causes the magnitudes of collected electron energy distributions to increase substantially but in many cases has little effect on their shape. Simple theoretical models are also developed that relate the photo- and thermionic emission processes and indicate that large numbers of photoexcited electrons partially thermalize (i.e., undergo one or more scattering events) before escaping from the emitter surface.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.