Study On Photoinduced Phenomena Of Ge-S Binery Chalcogenide Glass And Films

Ge-S chalcogenide glass and films are solids without long range order. As a consequence, they are intrinsically metastable. The structure and bond configurations of these disordered materials can be changes either by thermal treatment or by various external factors:light or other electromagnetic radiation, particle beams, electrical and magnetic fields, pressure, etc. The structure and properties of the glassy or amorphous chalcogenides can be modified. In addition with a higher glass transition temperature and larger range of transmission spectra, Ge-S chalcogenide glass and films have been applied in xerography, switching, holography and computer memories. Being a research focus, has become the trend.In this thesis, GeS4 bulk glass and GeS6 amorphous films were specially selected to be investigated and a nanosecond pulsed Nd:YAG laser at 532nm is induced. The as-prepared samples were characterized by XRD, Raman scattering, SEM, EDS, UV-Vis spectra, and so on. The relationship between structure changes and photoinduced phenomena was discussed. The main results are concluded as follows:(1) The Bragg reflector was fabricated by photoinduced refractive index change (PRC) in GeS4 bulk glass by linear polarized light, and the results reveal that the response rate of PRC increase with laser power intensity.(2) When illuminated by a linear polarized light Second Harmonic Generation (SHG) was observed in GeS4 bulk glass. It is explained by Tikhomirov model and convinced that the SHG is another evidence of photoinduced anisotropy in chalcogenide glasses.(3) Photodarkening phenomena were found in GeS6 amorphous films after exposure by a linear polarized light with a wavelength of 532nm. During the exposure process the non-bonding lone pair electrons in the chalcogenide atoms were excited and the structure and bond configuration were changed.(4) The optical properties of GeS6 amorphous films were analyzed by Swanepoel model according to its transmission spectrum. The refractive index increases with the exposure time.(5) The relaxation process occurred in Ge-S based chalcogenide glass and films after illumination because of its flexible structure and bond configuration.