Enhancing Field Emission in Air via Ultrascaled Nanorod\nElectrodes

Enhancing field emission in ultrascaled\nelectronics improves the\ndevice performance and energy efficiency. Conventional lithography\ndefines electrodes with a few-nanometer spacing on the cost of strengthened\nelectron scattering and the reduced field enhancement factor, thus\npresenting challenges to enhance field emission at a small bias. Here,\nwe used self-assembled nanorods with sub-5 nm spacing as electrodes\nto overcome these challenges. Intrinsic ballistic transport through\nhigh-crystallinity solution-synthesized nanorods minimized charge\nscattering; meanwhile ultrascaled anisotropic morphologies concentrated\nlocal electric fields and thereby lowered the barrier height. Enabled\nby these structural features, we demonstrated field emission density\nup to 4.1 × 10<sup>4</sup> A cm<sup>–2</sup> at 1 V in\nair, more than 10-fold higher than typical molecular and vacuum electronics\nat similar conditions, and constructed an air-operating electron source\nwith an on/off ratio of 10<sup>5</sup> at the collector electrode.\nEnergy-efficient high-conductance electron emission suggested the\npotential of using solution-synthesized nanomaterials in ultrascaled\nelectronics.