The crystallization process of Se77.5Te15Sb7.5 glass is studied by differential scanning calorimetry (DSC) technique under non-isothermal conditions at various heating rates. The crystallization parameters are deduced using different models. The validity of the Johnson
Mehl
Avrami (JMA) model to describe the crystallization process for the studied composition is investigated. Comparing experimental and calculated DSC curves indicate that the crystallization process of Se77.5Te15Sb7.5 glass cannot satisfactorily be described by the JMA model. In general, simulation results indicate that the Sestak
Berggren model is more suitable to describe the crystallization kinetics. The crystalline phases are identified using the X-ray diffraction technique and scanning electron microscopy.

Chalcogenide thin films of Se82.5Te15Sb2.5 with different thickness (50e300 nm) are prepared by thermal evaporation technique. Crystalline phases of the deposited films are identified by x-ray diffraction (XRD). The influence of the film thickness and annealing temperature on the structure is studied by using XRD. The XRD studies show that the crystallinity improved by increasing film thickness and annealing temperature. Furthermore, the particle size and the crystallinity increase whereas dislocation density and strain decrease with increasing both the film thickness and annealing temperature. Transmittance and reflectance of the films are measured in wavelength range 300e2500 nm. It is found that, the optical energy gap, Eg, decreases and the localized state tails, Ee, increases by increasing film thickness and annealing temperature. Dispersion of the refractive index is described using WempleeDiDomenico (WDD) single oscillator model. Dispersion parameters are calculated as a function of the film thickness and annealing temperature.

Chalcogenide thin films of Se82.5Te15Sb2.5 with different thickness (50e300 nm) are prepared by thermal evaporation technique. Crystalline phases of the deposited films are identified by x-ray diffraction (XRD). The influence of the film thickness and annealing temperature on the structure is studied by using XRD. The XRD studies show that the crystallinity improved by increasing film thickness and annealing temperature. Furthermore, the particle size and the crystallinity increase whereas dislocation density and strain decrease with increasing both the film thickness and annealing temperature. Transmittance and reflectance of the films are measured in wavelength range 300e2500 nm. It is found that, the optical energy gap, Eg, decreases and the localized state tails, Ee, increases by increasing film thickness and annealing temperature. Dispersion of the refractive index is described using WempleeDiDomenico (WDD) single oscillator model. Dispersion parameters are calculated as a function of the film thickness and annealing temperature.

Chalcogenide thin films of Se82.5Te15Sb2.5 with different thickness (50e300 nm) are prepared by thermal evaporation technique. Crystalline phases of the deposited films are identified by x-ray diffraction (XRD). The influence of the film thickness and annealing temperature on the structure is studied by using XRD. The XRD studies show that the crystallinity improved by increasing film thickness and annealing temperature. Furthermore, the particle size and the crystallinity increase whereas dislocation density and strain decrease with increasing both the film thickness and annealing temperature. Transmittance and reflectance of the films are measured in wavelength range 300e2500 nm. It is found that, the optical energy gap, Eg, decreases and the localized state tails, Ee, increases by increasing film thickness and annealing temperature. Dispersion of the refractive index is described using WempleeDiDomenico (WDD) single oscillator model. Dispersion parameters are calculated as a function of the film thickness and annealing temperature.

Crystallization process of Se85-xTe15Sbx (x = 2.7, 7.5, 10 and 15 at %) chalcogenide glasses has been studied by using differential scanning calorimetry (DSC) with different heating rates. These glasses are found to have a double glasses transition and overlapped crystalline phases for Se70Te15Sb15 glass while single glasses transition and single crystallization stage for other glasses. Glass transition temperature, Tg, onset crystallization temperature, Tc, and peak crystallization temperature, Tp, are found to be dependent on composition and heating rates. Values of various kinetic parameters such as activation energy of glass transition, Eg, activation energy of crystallization, Ec, Hurby number, Hr, thermal stability, Sp, rate constant, Kp, and Avrami exponent, n, are determined for the present systems. Results indicate that rate of crystallization is dependent on thermal stability and glass-forming ability. Crystallization mechanism occurs in two dimensions for studied compositions. Crystalline phases resulting from DSC and scanning electron microscopy have been identified by using X-ray diffraction.

Crystallization process of Se85-xTe15Sbx (x = 2.7, 7.5, 10 and 15 at %) chalcogenide glasses has been studied by using differential scanning calorimetry (DSC) with different heating rates. These glasses are found to have a double glasses transition and overlapped crystalline phases for Se70Te15Sb15 glass while single glasses transition and single crystallization stage for other glasses. Glass transition temperature, Tg, onset crystallization temperature, Tc, and peak crystallization temperature, Tp, are found to be dependent on composition and heating rates. Values of various kinetic parameters such as activation energy of glass transition, Eg, activation energy of crystallization, Ec, Hurby number, Hr, thermal stability, Sp, rate constant, Kp, and Avrami exponent, n, are determined for the present systems. Results indicate that rate of crystallization is dependent on thermal stability and glass-forming ability. Crystallization mechanism occurs in two dimensions for studied compositions. Crystalline phases resulting from DSC and scanning electron microscopy have been identified by using X-ray diffraction.

Crystallization process of Se85-xTe15Sbx (x = 2.7, 7.5, 10 and 15 at %) chalcogenide glasses has been studied by using differential scanning calorimetry (DSC) with different heating rates. These glasses are found to have a double glasses transition and overlapped crystalline phases for Se70Te15Sb15 glass while single glasses transition and single crystallization stage for other glasses. Glass transition temperature, Tg, onset crystallization temperature, Tc, and peak crystallization temperature, Tp, are found to be dependent on composition and heating rates. Values of various kinetic parameters such as activation energy of glass transition, Eg, activation energy of crystallization, Ec, Hurby number, Hr, thermal stability, Sp, rate constant, Kp, and Avrami exponent, n, are determined for the present systems. Results indicate that rate of crystallization is dependent on thermal stability and glass-forming ability. Crystallization mechanism occurs in two dimensions for studied compositions. Crystalline phases resulting from DSC and scanning electron microscopy have been identified by using X-ray diffraction.

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