Three-dimensional branched SiC nanowire field emitters with single-crystal integrated structures and increased emission sites: ultralow turn-on field and high stability

Abstract

Low turn-on field (E_to) and high current emission stability of cold field emission (FE) cathodes are crucial for their practical application in electronic devices. However, the FE cathodes’ emission sites are still weaker and insufficient for use in actual applications. These issues can be resolved by focusing on the design and assembly of the individual building blocks into a specific three-dimensional (3D) structure. In the current study, a single-crystal integrated N-doped 3D branched SiC nanowire FE cathode was fabricated by controlling the epitaxial growth of high-density SiC dendrites around the SiC backbone nanowires. These nanowires were obtained via repeated pyrolysis of a polymeric precursor and the facile in situ gas-phase cation exchange technique. In addition to offering a large number of electron emission sites, the sturdy 3D branched SiC nanowires may prevent structure degradation brought on by electrostatic forces and Joule heat during long-duration FE operation. The E_to and field enhancement factor (β) of the branched SiC field emitters are respectively measured to be 0.61 V μm⁻¹ and 9530, which are superior in comparison to the majority of reported SiC nanostructure-based FE cathodes. In addition, the cathode possesses extremely high electron emission stability with only 3.5% fluctuation in current emission over a 10 h long operation, suggesting that the findings of the present investigation could furnish a solid foundation for the application of SiC nanostructures as high-performance FE cathodes.