@phdthesis{oai:tsukuba.repo.nii.ac.jp:00008710,
 author = {Matsuishi, Kiyoto and 松石, 清人},
 month = {},
 note = {The Role of intermediate range interactions on physical properties is discussed for various chalcogenide glassy semiconductors. Moreover, emphasis is also placed on the influence of geometrical restriction and energetic disorder to the structural relaxation in glass transition region.  The Ramen scattering and the infrared spectra of chalcogenide glassy semiconductors were measured in order to obtain the information about the structural order through the vibrational properties. The vibrational spectra indicate clearly the presence of some kind of order beyond a molecular unit. The vibrational mode-assignment to the resolved components in the second-order Ramen scattering spectra suggests that the occurrence of combination modes is strongly selective and may be related to the strength of interaction between vibrational units. The analysis of the strongly selective combination modes leads us to conclude that vibrational interacting ranging over more than two molecular units are very important for the understanding of the two-phonon vibrational properties.  The low frequency optical absorption spectra of various chalcogenide glassy semiconductors were measured in the wavenumber region 7-30 cm[?] . The magnitude and the correlation length f the spatial fluctuation of charges are obtained from the best fit of the observed spectrum to the theoretical curve calculated using the charge-fluctuation model. The magnitudes of the charge fluctuation for various chalcogenide glasses correspond in common to about 10 % of the effective charges obtained from the Reststrahlen bands in spite of the difference of microstructure in those glasses. For a-As2S3 and a-As2Se3, the presence of an intralayer correlation ranging over about 7 A as an intermediate range order is confirmed from the correlation effect of the charge fluctuation. This dimension 7 A may be responsible for the diameter of a ring-like structure within a layer.  For a-Se1-xTex and a-(As2S3)100-xAgx Systems, we have investigated the composition dependence of the physical  properties which are expected to be more sensitive to molecularity or bond connectivity. The composition dependence of the physical properties exhibits critical behavior near x=0.15 for a-Se1-xTex system and near x=2 for a-(As2S3)100-xAgx system. These results are interpreted in terms of intermediate range It is suggested that the weak, but important, intermediate range non-bonding forces affect strongly the structural order and the character of the glassy state.  We have studied the structural relaxation in glass transition region through the heat capacity data obtained on DSC experiment. It is found that the Kohlrausch-Williams-Watts form, [?](t)~exp(-(t/[?])β), is a characteristic relaxation function which can describe the structural relaxation in glasses. For acquiring additional information to specify the microscopic mechanism, we discuss the structural relaxation in a-As2S3 through the annealing effect and the Ag-doping effect. It is shown that the kinetics of structural relaxation during annealing can be readily understood in terms of a hierarchical energy landscape. This leads us to conclude that the hierarchical distribution of energy barriers is important for the understanding of the dynamics of structural relaxation. From analyses of the KWW-behavior on structural relaxation in Ag-doped a-As2S3, it is realized that the KWW-behavior depends strongly on the underlying geometry and that the parameter β serves as an indicator of the geometrical restriction or fractal dimension., 1988},
 school = {筑波大学, University of Tsukuba},
 title = {Intermediate range correlations and geometrical restrictions in chalcogenide glassy semiconductors},
 year = {1989}
}