• 文献标题:   Monochromatic Photocathodes from Graphene-Stabilized Diamondoids
  • 文献类型:   Article
  • 作  者:   YAN H, NARASIMHA KT, DENLINGER J, LI FH, MO SK, HOHMAN JN, DAHL JEP, CARLSON RMK, TKACHENKO BA, FOKIN AA, SCHREINER PR, HUSSAIN Z, SHEN ZX, MELOSH NA
  • 作者关键词:   diamondoid, graphene, monochromatic, photoemission, negative electron affinity
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:   Stanford Univ
  • 被引频次:   2
  • DOI:   10.1021/acs.nanolett.7b04645
  • 出版年:   2018

▎ 摘  要

The monochromatic photoemission from diamondoid monolayers provides a new strategy to create electron sources with low energy dispersion and enables compact electron guns with high brightness and low beam emittance for aberration-free imaging, lithography, and accelerators. However, these potential applications are hindered by degradation of diarnondoid monolayers under photon irradiation and electron bombardment. Here, we report a graphene-protected diamondoid monolayer photocathode with 4-fold enhancement of stability compared to the bare diamondoid counterpart. The single-layer grapheme overcoating preserves the monochromaticity of the photoelectrons, showing 12.5 meV ful width at half-maximum distribution of kinetic energy. Importantly, the graphene coating effectively suppresses desorption of the diamondoid monolayer, enhancing its thermal stability. by at least 100 K. Furthermore, comparing the decay rate at different photon energies, we identify electron bombardment as the principle decay pathway for diamondoids under graphene protection. This provides a generic approach for stabilizing volatile species on photocathode surfaces; which could greatly improve performance of electron emitters.