Sc-Containing (Scandate) Thermionic Cathodes: Mechanisms for Sc Enhancement of Emission

Mujan N. Seif, Qunfei Zhou, Xiaotao Liu, T. John Balk, Matthew J. Beck

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Although thermionic emission has been studied for more than 100 years, recent interest in novel electron devices for military and civilian use has led to a surge in demand for cathodes with enhanced emission properties (e.g., higher current density, more uniform emission, lower operating temperatures, or extended in-service longevity). Sc-containing 'scandate' cathodes have been widely reported to exhibit superior emission properties compared to previous-generation thermionic cathodes, including oxide, B-, and M-type cathodes. Despite extensive study spanning several decades, the mechanism by which the addition of Sc enhances cathode emission remains ambiguous, and nonuniform emission, low reproducibility, and inconsistent longevity continue to prevent widespread commercial integration of scandate cathodes into electron devices. This second part of a two-part review explores the various mechanisms proposed for how Sc enhances electron emission and summarizes ongoing scientific challenges relating to the development and deployment of scandate cathodes.

Original languageEnglish
Pages (from-to)3523-3534
Number of pages12
JournalIEEE Transactions on Electron Devices
Issue number7
StatePublished - Jul 1 2022

Bibliographical note

Publisher Copyright:
© 1963-2012 IEEE.


  • Dispenser cathode
  • review
  • scandate cathode
  • thermionic cathode

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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