Photocathode electron beam sources using GaN and InGaN with NEA surface

T. Nishitani, T. Maekawa, M. Tabuchi, Takashi Meguro, Y. Honda, H. Amano

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

12 Citations (Scopus)


A photocathode electron source using p-type GaN and p-type InGaN semiconductors with a negative electron affinity (NEA) surface has been studied for its ability to maintain an extended NEA state. The key technology of NEA photocathodes is the formation of electric dipoles by atoms on the surface, which makes it possible for photo excited electrons in the conduction band minimum to escape into the vacuum. This means that in order to keep the electron energy spread as small as possible, the excitation photon energy should be tuned to the band gap energy. However, the NEA surface is damaged by the adsorption of residual gas and the back-bombardment of ionized residual gas by photoelectrons. The p-type GaN and InGaN semiconductors were measured a lifetime of quantum yield of excitation energy corresponding to the band gap energy in comparison to the p-type GaAs as the conventional NEA photocathode. Lifetime of NEA-photocathodes using the GaN and InGaN were 21 times and 7.7 times longer respectively than that using the GaAs.

Original languageEnglish
Title of host publicationGallium Nitride Materials and Devices X
EditorsJen-Inn Chyi, Hadis Morkoc, Hiroshi Fujioka
ISBN (Electronic)9781628414530
Publication statusPublished - 1 Jan 2015
EventGallium Nitride Materials and Devices X - San Francisco, United States
Duration: 9 Feb 201512 Feb 2015

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceGallium Nitride Materials and Devices X
Country/TerritoryUnited States
CitySan Francisco


  • Electron beam
  • GaN
  • InGaN
  • NEA surface
  • Photocathode


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