A HfC nanowire point electron source with oxycarbide surface of lower work function for high-brightness and stable field-emission

• Published in: Nano research 2020-06, Vol.13 (6), p.1620-1626
• Main Authors: Tang, Shuai, Tang, Jie, Chiu, Ta-wei, Hayami, Wataru, Uzuhashi, Jun, Ohkubo, Tadakatsu, Uesugi, Fumihiko, Takeguchi, Masaki, Mitome, Masanori, Qin, Lu-Chang
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Brightness; Chemistry and Materials Science; Condensed Matter Physics; Density functional theory; Electric fields; Electron emission; Electronic devices; Electrons; Emission measurements; Emitters; Emitters (electron); Field emission; Hafnium carbide; Hydrofluorocarbons; Materials Science; Nanotechnology; Nanowires; Oxycarbides; Research Article; Single crystals; Spectroscopy; Ultrahigh vacuum; Vacuum; Work functions; X ray tubes
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-020-2782-0

Electric field-induced point electron source is highly demanded for microscopy, spectroscopy, lithography, X-ray tubes, microwave devices, and data displays. However, the instability in emission current and requirement of ultrahigh vacuum have often limited its extensive applications. Herewith we report a single-crystalline HfC nanowire with oxycarbide emission surface for stable electron emission at 50 nA with fluctuations less than 1% in a vacuum of 4 × 10 −7 Pa. The emitter has a low work function of 2.5 eV measured by the field emission Fowler-Nordheim curve and it is in good agreement with density functional theory (DFT) calculations. The energy spread is in a range of 0.21–0.26 eV with a corresponding reduced brightness 1.95 × 10 11 −3.81 × 10 11 A·m −2 ·sr −1 ·V −1 . The HfC nanowire with oxycarbide emission surface is a qualified candidate for the next-generation electron source with high brightness, large current, and low energy spread.