الفهرس 
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Abstract
Summary
The present thesis is devoted to study the structural identification, optical, crystallization kinetics, DC electrical conductivity, AC conductivity and dielectric properties of Se98Te2 and Se96Te2X2 (X = Cd, Zn) glassy alloys. The studied compositions were prepared in bulk form by quenching the molten materials in an ice-water after synthesis in an oscillatory furnace according to a special regime in an evacuated silica tube and then thin film form bulk compositions by thermal evaporation technique.
X-ray diffraction analysis (XRD) showed that, the prepared samples in powder and thin films form are in the amorphous state.
Energy dispersive X-ray analysis (EDX) for the investigated composition indicates that the real percentage of the constituted elements in the investigated compositions are close to that preparation.
The optical properties of Se98Te2 and Se96Te2X2 (X = Cd, Zn) thin films are studied. Transmittance and reflectance were measured at room temperature for samples of different thicknesses in the range (200-670nm) in the wavelength range (400-2500nm) to calculate the optical constants (refractive index 𝒏, absorption index 𝒌 and absorption coefficient 𝜶) using Swanepoel method.
The allowed optical transition is found to direct and indirect transition and optical band gap 𝑬𝒈𝒅𝒊 ,𝑬𝒈𝒊𝒏𝒅 decreases with addition Cd, Zn but the width the tail of localized states 𝑬𝒆 the increases with metal additives Cd, Zn.
Study of the crystallization kinetics for the investigated chalcogenide glasses in powder form has been discussed under non-isothermal conditions using differential thermal analysis DTA. Using different heating rates, the
Summary
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