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HfC nanoneedles with both excellent electron emission characteristics and robust structure are promising field-emission point electron sources, especially for applications desiring a high emission current. Herewith we report successful fabrication of HfC nanoneedle emitter by focused ion beam and its characterization. Transmission electron microscopy and energy dispersive X-ray spectroscopy examinations show that the HfC nanoneedle has a sharp tip with a radius of curvature of about 10 nm. Its atomic structure remains crystalline and it is aligned in a <100> direction. The HfC nanoneedle emitter has a low work function of 3.2 eV. It delivers an electron beam with a low turn-on field of 2.7 V/nm (at emission current of 2 nA) and a threshold field of 3.5 V/nm (at emission current of 50 nA), respectively. The HfC nanoneedle emitter also exhibits an excellent emission stability with a fluctuation of 1.5 % in 15 min under a high current (280 nA). The excellent current stability is attributed to the sharp tip lowering the extraction voltage that reduced ion bombardment and oxidation of the emitter surface with lowered activities in gas adsorption or desorption.

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• In Copyright
  

Keyword: electron emission, transmission electron microscopy, focused ion beam

Date published: 2025-03-06

Publisher: Elsevier BV

Journal:

• Vacuum (ISSN: 0042207X) vol. 238 114224

Funding:

Manuscript type: Author's original (Submitted manuscript)

MDR DOI: https://doi.org/10.48505/nims.5417

First published URL: https://doi.org/10.1016/j.vacuum.2025.114224

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Updated at: 2025-04-12 08:30:10 +0900

Published on MDR: 2025-04-11 20:23:09 +0900