Sputtered thin films of amorphous tungsten oxide were deposited onto glass substrates coated by conductive indium- tin oxide. The films were sputtered in Ar/O₂ with different oxygen contents. Elastic Recoil Detection Analysis determined the density and the stoichiometry while x-ray diffraction gave evidence of the amorphous character. The films were electrochemically intercalated with lithium ions. At several intercalation levels the optical reflectance and transmittance was measured in the wavelength range 0.3 micrometers to 2.5 micrometers . We study the effect of different sputtering conditions on the coloration efficiency of the films. Films deposited at pressures of 80 mTorr showed a distinctly different absorption spectrum after intercalation, as compared to films sputtered at lower pressure. Sputtered substoichiometric tungsten oxide exhibits an absorption peak similar to the case of lithium intercalation. Substoichiometric films can be made transparent by deintercalation.

Date Published: 13 November 2001
PDF: 8 pages
Proc. SPIE 4458, Solar and Switching Materials, (13 November 2001); doi: 10.1117/12.448248

Published in SPIE Proceedings Vol. 4458:
Solar and Switching Materials
Carl M. Lampert; Carl M. Lampert; Claes-Goran Granqvist; Claes-Goeran Granqvist; Keith L. Lewis; Keith L. Lewis, Editor(s)