ISSN:
1432-0630
Keywords:
78.20
;
42.80
;
85.60
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The fundamental absorption edge of evaporated WO3 films is investigated. The optical gap of the virgin film is estimated to be 3.41 eV at room temperature and it decreases with increase of annealing temperature up to 200°C. Annealing at 300°C leads to change in the spectral shape, which is caused by crystallization. For the films annealed at 200°C, temperature coefficient of the optical gap is estimated to be −2×10−4 eV/K and the slope of Urbach's tail is found to be independent of measuring temperature up to 200°C. With electrolytic coloration, shift of the optical gap toward higher energy is observed. Magnitude of this shift is estimated to be 0.05 eV at the color center concentration of 7.5×1021 cm−3 when H+ electrolyte is used. If Li+ electrolyte is used, the magnitude of this shift is about three times larger than in the case of H+ electrolyte. This fact is interpreted by a small change in the host matrix structure owing to the injection of proton or Li+ during coloration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00900398
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