Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1497325 | Optical Materials | 2008 | 5 Pages |
Abstract
The influence of light illumination on the optical constants of chalcogenide thin films with non-stoichiometric GexSb20âxTe80 (x = 15, 17, 19) composition is studied by spectral ellipsometry in the visible range of light. The films were deposited onto glass substrates by vacuum thermal evaporation of parent glasses and were subjected to an 1-h illumination with a 500 W HBO mercury lamp. It has been established that illumination of the films leads to a decrease of the refractive index, n, in the whole spectral region studied and to an increase of the extinction coefficient, k, in the range of 600-800 nm. The optical bandgap energy Eg values are within 0.55-0.76 eV with a tendency to increase with increasing the Ge content. Illumination resulted in a sharp decrease of the Eg values indicating structural change in the films. Leaving the films at atmospheric conditions the optical parameters values change toward their initial values of unilluminated state.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
V. Pamukchieva, A. Szekeres,