Field Electron Emission Characteristics of Single-Crystal GdB6 Conductive Ceramics.

Large-size and high-quality single-crystal GdB₆ conductive ceramics (length greater than 35 mm and diameter greater than 6 mm) were prepared by optical zone melting, and the single-crystal quality was characterized by single-crystal diffraction, Laue photo, crystal plane rocking curve, and single-crystal fracture scan. Electrochemical corrosion equipment of single-crystal GdB₆ conductive ceramic tips was newly designed, which greatly reduced the preparation time of tips from more than 10 h to 2.75 h. The field electron emission current density of the single-crystal GdB₆ conductive ceramic tip (r ≈ 500 nm) prepared by the device under applied voltage (2550 V) is 2.24 × 10⁴ A/cm². This paper also theoretically calculates the electronic structure and electron work function of single-crystal GdB₆ under a strong electric field (0.1 V/Å). The trapping ability of the B-octahedron in the single crystal GdB₆ conductive ceramics against the free electrons of Gd is greatly weakened under a strong electric field (0.1 V/Å), and the free electrons also have a certain enrichment phenomenon on the surface of GdB₆. The surface barrier of single-crystal GdB₆ conductive ceramic will be shortened and narrowed sharply due to the strong electric field (0.1 V/Å), which causes the work function of (100) crystal plane of single-crystal GdB₆ to decrease sharply (0.38 eV). This causes the free electrons in Gd to have greater energy at the time of emission, and it is easier to get rid of the trap of surface barriers, which is conducive to field electron emission. [ABSTRACT FROM AUTHOR]