CHARACTERIZATION OF HIGH-TEMPERATURE REACTIONS AT THE BAO W INTERFACE/

Authors
Citation
Jn. Shi et Dl. Allara, CHARACTERIZATION OF HIGH-TEMPERATURE REACTIONS AT THE BAO W INTERFACE/, Langmuir, 12(21), 1996, pp. 5099-5108
Citations number
32
Categorie Soggetti
Chemistry Physical
Journal title
ISSN journal
07437463
Volume
12
Issue
21
Year of publication
1996
Pages
5099 - 5108
Database
ISI
SICI code
0743-7463(1996)12:21<5099:COHRAT>2.0.ZU;2-W
Abstract
Thin (similar to 10 nm) BaO films on tungsten substrates, prepared at specific coverages from multilayer Langmuir-Blodgett precursor films, were heated to different temperatures between 200 and 1200 degrees C i n a vacuum environment. The chemical changes occurring at the BaO/W in terface were characterized by X-ray photoelectron spectroscopy, infrar ed reflection spectroscopy, spectroscopic ellipsometry, and X-ray diff raction analyses. The results show that a BaWO4 phase forms above an a pproximate threshold temperature of 800 degrees C and, contrary to pre vious observations reported for heterogeneous reactions in powders, no evidence for a Ba3WO6 phase is seen. These data form a fundamental ba sis for understanding the regulation of the emission work function in the operation of an alkaline-earth-coated tungsten cathode fluorescent lamp.