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Surface and optical characterization of yttrium hydride films deposited on regular glass to be used as switchable mirrors
Author(s) -
Velásquez P.,
Castañer R.,
de la CasaLillo M. A.,
SánchezLópez M. M.,
Mallavia R.,
Moreno I.,
Gutiérrez A.,
Mateos F.
Publication year - 2002
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.1307
Subject(s) - yttrium , materials science , x ray photoelectron spectroscopy , hydride , palladium , thin film , transmittance , hydrogen , impurity , analytical chemistry (journal) , metal , chemical engineering , nanotechnology , chemistry , metallurgy , optoelectronics , oxide , catalysis , organic chemistry , engineering
Yttrium and palladium thin films deposited on glass have been characterized by means of XPS depth profiling, SEM, energy‐dispersive x‐ray spectroscopy and ultraviolet–visible spectroscopy. These films allow optical windows of variable transparency to be obtained based on the formation of yttrium hydride by hydrogenation, with the palladium film working as a barrier against yttrium oxidation but being permeable to hydrogen. The transformation of yttrium into its hydride is concomitant with a metal–semiconducting transition that changes the physical properties of the material, especially its optical behaviour: the transmittance in the visible range goes from 0% for the metallic state to 30–70% for the hydrogenated state. In this work, the preparation conditions of optical windows using low‐cost regular glass as substrate have been optimized, both regarding the deposition and the hydrogenation. Uniform films free of impurities, such as oxygen and carbon, have been obtained under ultrahigh vacuum conditions of ∼10 −7 Pa. Deposition has been performed by electron bombardment of the material, using palladium and yttrium of high purity. Copyright © 2002 John Wiley & Sons, Ltd.