| AVS 54th International Symposium | |
| Advanced Surface Engineering | Tuesday Sessions |
| Session SE-TuA |
| Session: | Naturally and Artificially Nanolaminated Coatings |
| Presenter: | M.V. Sopinskyy, V. Lashkaryov Institute of Semiconductor Physics, Ukraine |
| Authors: | M.V. Sopinskyy, V. Lashkaryov Institute of Semiconductor Physics, Ukraine V.I. Min’ko, V. Lashkaryov Institute of Semiconductor Physics NAS, Ukraine I.Z. Indutnyy, V. Lashkaryov Institute of Semiconductor Physics, Ukraine O.S. Lytvyn, V. Lashkaryov Institute of Semiconductor Physics, Ukraine P.E. Shepeliavyi, V. Lashkaryov Institute of Semiconductor Physics, Ukraine |
| Correspondent: | Click to Email |
In this report we present the first results on the surface morphology and optical properties of 1-3 mkm thick As2S3 films that were thermally evaporated on the glass and silicon substrates within 70-80° range of the vapor incidence angles. The AFM has revealed the details of the surface relief of glancing-deposited films showing quasi-regular grating-like structure, with the spatial frequency of quasi-gratings being in the 3000-6000 mm-1 range, and relief depth of 10-60 nm range. Ordering degree also depends on the substrate. The preliminary deposition of thin Cr film on the glass substrate results in more pronounced surface self-ordering of glancing-deposited As2S3 films. Multiangle ellipsometric measurements have been performed to determine the refractive index, and check the anisotropy of the films. It has been found that the refractive index values in these films are lower compared to the values for the films with the normal (perpendicular) deposition. In addition, there is anisotropy of refractive index in the plane of the film. This indicates that the structure of the films is columnar, with the columns tilted relative to the substrate normal. The most probable explanation for the observed effect is the surface stress that plays significant role in the self-organized ordering of nanostructures at the mesoscopic length scales (several nm - hundreds of nm). It is the known fact that the thermally deposited As2S3 films are mechanically stressed, especially in the near-surface area. Thus, due to the structural anisotropy of the obliquely deposited As2S3 films, the stress forces are also anisotropic. The more pronounced columnar structure of these samples provides a lot of free space where the bond breaking and atomic movements are facilitated. Both of these factors result in anisotropic plastic shears in the film’ near-surface region. The effect is a cheap and easy way to create quasi-gratings on the surface of amorphous chalcogenide films and could be used for fabrication of nano- and microdevices.