Diamond p-i-n-nanoC diodes for electron emitters

Franz A. Koeck, Manpuneet Benipal, Harshad Surdi, Robert J. Nemanich

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Electron emitters are widely deployed in traveling wavetubes (TWTs) for communications, radar applications, and scientific apparatus like free electron lasers. These instruments typically utilize cathodes that release an electron current through application of thermal energy or high electric fields. A novel electron emitter approach exploits the negative electron affinity surface of diamond in a modified semiconductor p-i-n diode. Under a forward bias electrons are injected into the conduction band of the diamond diode and a fraction are emitted into vacuum. Electron emission occurs at room temperature and low electric fields. We have prepared a modified diamond p-i-n diode that included a highly conducting nanostructured carbon (nanoC) contact layer utilizing plasma-enhanced chemical vapor deposition (PECVD) on a single crystal boron doped substrate. Emitter devices with various geometries were then fabricated using photo-lithography. After a hydrogen passivation step individual devices were characterized in vacuum. Under a forward bias the p-i-n-nanoC diodes displayed light emission indicative of bipolar transport. With a typical diode current of 0.1A an electron emission current approaching 0.4mA was measured from a single device sized 1.2mm x 0.2mm.

Original languageEnglish (US)
Title of host publication2020 IEEE 21st International Conference on Vacuum Electronics, IVEC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages2
ISBN (Electronic)9781538682883
StatePublished - Oct 19 2020
Event21st IEEE International Conference on Vacuum Electronics, IVEC 2020 - Monterey, United States
Duration: Oct 19 2020Oct 22 2020

Publication series

Name2020 IEEE 21st International Conference on Vacuum Electronics, IVEC 2020


Conference21st IEEE International Conference on Vacuum Electronics, IVEC 2020
Country/TerritoryUnited States


  • Diamond
  • Doping
  • Electron emission
  • Electronic material
  • Plasma-enhanced chemical vapor deposition

ASJC Scopus subject areas

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


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