Chalcogenide glasses have attracted considerable attention due to their infrared
transparency, low phonon energy, and high non linear optical properties. They have been
explored as promising candidate for optical memories, gratings, switching devices etc.
Because of their low phonon energy and high refractive indices, now a days these are used for high efficiency fibre amplifiers. Nevertheless, the availability of amorphous
semiconductors in the form of high quality multilayers provides potential applications in the field of micro and optoelectronics. Among amorphous multilayers, chalcogenide
multilayers are attractive because of the prominent photoinduced effects. Studies in
chalcogenide amorphous multilayer have been directed towards two phenomena. One is
photoinduced interdiffusion in short period multilayer systems which finds potential
applications in holographic recording and fabrication of phase gratings . The other is photo darkening or photobleaching which is also known in thick films. These multilayers exhibit prominent photoinduced effects, similar to those exhibited by uniform thin films. In spite of its practical usefulness, the mechanism of photoinduced interdiffusion is not properly understood. Since most structural transformations are related to atomic diffusion, understanding of the structural transformation must be based on the diffusion process.
The main aim of this thesis is to study the photoinduced diffusion in Sb/As2S3
multilayered films and (As2S3)1-xSbx thin films. In literature, there are reports about the
photoinduced interdiffusion in Se/As2S3 and Bi/As2S3 multilayered films, but the
mechanisms of photoinduced interdiffusion of these elements are not very clear. Raman
scattering and infrared spectroscopy techniques have been used to study the photoinduced
interdiffusion in Se/As2S3 and Bi/As2S3 multilayered films by Malyovanik et al.
(M. Malyovanik, M. Shiplyak, V. Cheresnya, T. Remeta, S. Ivan, and A. Kikineshi, J.
Optoelectron. Adv. Mater. 5, 397 (2003). But many questions remain unanswered. The
characteristic spectra of components in the multilayer and those of the diffused layer were rather similar. In the present thesis, photoinduced interdiffusion in Sb/As2S3 multilayered samples are studied by Fourier Transform Infrared spectroscopy (FTIR) at room and low temperature and X-ray photoelectron spectroscopy (XPS). The photoinduced effects in (As2S3)1-xSbx thin films are studied by FTIR, XPS and Raman Spectroscopy. The detailed information about the distribution of electronic states in the absorption edge, localized states and the new bonds formed between the components due to photoinduced interdiffusion elucidated from the above studies will give more insight into the mechanism and kinetics of photoinduced interdiffusion. The thesis consists of seven chapters. References are given at the end of each chapter.
| Identifer | oai:union.ndltd.org:IISc/oai:etd.ncsi.iisc.ernet.in:2005/2017 |
| Date | 07 1900 |
| Creators | Naik, Ramakanta |
| Contributors | Sangunni, K S |
| Source Sets | India Institute of Science |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Relation | G23532 |
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