Nano-Cold-Cathode Electron Source Based on Plasmon-Mediated Emission

To address the developmental requisites of the emerging generation of vacuum micro- and nanoelectronic devices, cathode electron sources are evolving toward enhanced efficiency, heightened brightness, diminished energy consumption, and enhanced tunability. The pursuit of nano-cold-cathodes with plasmon-enhanced properties emerges as a potent strategy to realize these objectives. In this study, we propose a novel large-current, high-brightness needle-like nano-cold-cathode electron source designed with photoelectric synergistic excitation. This cathode is constructed using a composite material comprising plasmonic gold (Au) nanoparticles and a high-melting-point metal tungsten (W) needle. The resulting Au-on-W needle nano-cold-cathode demonstrates outstanding electron emission characteristics: under the synergistic excitation of an electrostatic field below ∼0.35 V μm^–1 and an average laser intensity of ∼10 W cm^–2, the source achieved an emission current surpassing 830 nA and a reduced brightness of ∼1.1 × 10¹⁰ A m^–2 sr^–1 V^–1. This performance marks a remarkable enhancement, improving by one and 2 orders of magnitude when compared to W needle nano-cold-cathodes and commercial Schottky point electron source cathodes, respectively, thus underscoring its significant superiorities. In this photoelectric synergistic excitation mode, the Au-on-W cathode demonstrates tunable electron emission characteristics in response to the intrinsic properties of the incident laser, including frequency, amplitude, and polarization. These features can be achieved through the direct modulation of the structural features of the Au-on-W nano-cold-cathodes. This research endeavors to establish the groundwork for the development of a new class of tunable high-performance cathode electron source devices.