Abstract
Electron emissive thin films that possess the thermionic properties of macroscale dispenser cathodes have been fabricated using standard RF sputter deposition techniques. These films are based on a compositionally modulated structure using W and a Ba-containing ternary oxide. These films exhibit uniform work function values of 1.9 to 2.2 eV with high emission coefficients of 2 to 26 A·cm−2K−2. Electron microscopy shows that W layer coalescence and continued particle growth occurs with prolonged annealing, eventually disrupting the original surface layer. Chemical modification of the oxide during deposition may provide a route to limit the extent of W coalescence and preserve surface metallization layers on these films. These films are designed to be integrated into thermionic micro-devices.
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Zavadil, K.R., King, D.B. Thin Film Dispenser Cathodes for Thermionic Micro-Devices. MRS Online Proceedings Library 691, 113 (2001). https://doi.org/10.1557/PROC-691-G11.3
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DOI: https://doi.org/10.1557/PROC-691-G11.3