Impregnated cathode coated with tungsten thin film containing Sc2O3

Abstract

An impregnated cathode of a novel structure is proposed, fabricated, and evaluated. A thin tungsten film 100–400 nm in thickness containing various amounts of Sc2O3 is coated on a standard impregnated cathode composed of a porous tungsten body in which electron emissive materials are impregnated. The electron emission property measured with a diode configuration is found to be dependent on Sc2O3 content and surface atom distribution. Surface atom distribution is depicted by means of Auger electron spectroscopy. For high electron emission enhancement it is necessary for Sc2O3 content to be 2.5–6.5 wt. % and for a layer of the order of a monolayer in thickness composed of Ba, Sc, and O to develop on the cathode surface.

Fundamental physics of vacuum electron sources

“…Later in the late 1980s a high emission current density was reported by utilizing the MM cathode with a small amount of Sc 2 O 3 in the matrix [97]. Then, impregnated cathodes were investigated with the top layer consisting of a mixed matrix [98], a (W + Sc 2 O 3 ) thin film [99,100], a (W + Sc 2 W 3 O 12 ) thin film [101] prepared by sputtering and a top layer of Re/Sc 2 O 3 [102]. These top layered cathodes were found to show extremely good emission and outperformed M cathodes.…”

Tris(2,4‐pentanedionato)scandium(III) as a Precursor for Plasma‐Assisted Liquid Injection CVD to Deposit Nanocrystalline Scandia Thin Films

“…The physical gasphase methods used include electron beam [5] or laser beam evaporation, [4,16] and sputtering. [10,17] Direct evaporation and condensation [18,19] of Sc 2 O 3 under low pressure have also been employed. In addition, scandia films have been prepared by direct evaporation of metallic Sc followed by subsequent oxidation of the resulting scandium film.…”

Surface-Controlled Deposition of Sc2O3 Thin Films by Atomic Layer Epitaxy Using β-Diketonate and Organometallic Precursors

“…Sc 2 O 3 has also been used for the stabilization of ZrO 2 thin films and as a dopant in nickel copper oxide based NO x sensors . The use of Sc 2 O 3 in cathodes in high-resolution and high-brightness cathode ray tubes has also been studied. , In this application Sc 2 O 3 together with W improves the cathode emission capability, although better emission characteristics have been obtained by metallic scandium overlayers . Furthermore, Sc 2 O 3 has attracted interest as a constituent of ferroelectric thin films, such as Pb[(Sc 0.5 Nb 0.5 ) 0.57 Ti 0.43 ]O 3 15 and Pb(Sc 0.5 Ta 0.5 )O 3 . , These materials have been studied for pyroelectric imaging and piezoelectric applications.…”

“…More recently liquid-phase (sol−gel) techniques have also been applied . The physical gas-phase methods used include electron-beam 2 and laser-beam , evaporation and sputtering. , Direct evaporation and condensation , as well as reactive evaporation of Sc 2 O 3 at low pressure have also been employed. Furthermore, Sc 2 O 3 films have been prepared by direct evaporation of metallic Sc followed by subsequent oxidation of the resulting scandium film …”