Sunanda Sharda

Effect of Te on linear and non-linear optical properties of new quaternary Ge-Se-Sb-Te chalcogenide glasses

We report linear and non-linear optical properties of a new quaternary chalcogenide glass series Ge19-ySe63.8Sb17.2Tey (y = 0, 2, 4, 6, 8, 10). In linear optical properties; refractive index, extinction coefficient and the Tauc gap are reported and their variation with Te content has been discussed. In non-linear properties; third order nonlinear susceptibility and non-linear refractive index has been discussed. The variation of non-linear refractive index has also been reported with normalized photon energy. A correlation between the Tauc gap and nonlinear refractive index has been discussed. Results indicate that these materials may find applications in modern optical devices.

Structural Rigidity, Percolation and Transition-Temperature Study of the Ge19Se81-xSbx System

Selenium-based glasses are attractive candidate materials because of their low transmission losses and other optical properties. In the present paper, samples of Ge19Se81-xSbx (x = 0, 4, 8, 12, 16, 17.2, 20) were prepared by using the melt-quench technique, and their X-ray diffraction spectra were studied. Some of the physical parameters were calculated theoretically. It was observed that the glass transition temperature increased up to x = 17.2 and then decreased whereas the theoretically calculated band-gap decreased with increasing Sb content.

New Quaternary Sb-Se-Ge-In Chalcogenide Glasses: Linear and Nonlinear Optical Properties

Chalcogenide glasses find extensive applications in infrared (IR) devices and optical communication. Optical parameters of Sb10Se65Ge25−yIny thin films, deposited by the thermal evaporation technique, have been analyzed using ultraviolet–visible-near IR spectroscopy. The transitions in the forbidden gap are indirect. The effect of indium (In) alloying on the nonlinear optical parameters has been studied. A shift in optical absorption edge towards higher wavelength shows that the width of the localized states changes, which affects the optical parameters of the system. The high nonlinearity of these glasses makes them suitable for optical regeneration and Raman amplification.

Physical Analysis of Structural Transformation in Ge-Incorporated a-SbxSe100-x System

Chalcogenide glasses are suitable for far-infrared and imaging applications. In the present study, Sb10Se90-xGex (x=0, 19, 21, 23, 25, 27) system has been chosen to study structural transformations via physical parameters. Bulk samples with x = 0, 19, 21, 23, 25 and 27 have been prepared using the melt-quenching technique. A theoretical study of the ternary glass system revealed that there was a significant change in the structural environment of the system due to rigidity percolation, which took place as Se was replaced by Ge, and hence resulted in changes in other physical parameters of the system.

Effect of substitutional doping on temperature dependent electrical parameters of amorphous Se-Te semiconductors

Steady state current-voltage characteristics of the amorphous (Se80Te20)98Y2 (Y = Ag, Bi, Ge, Cd) semiconductors at different temperatures are reported. The measurements were performed using direct-current voltage bias to understand the basic conductivity mechanism and to evaluate the impact of each substituent on electrical response. The space charge limited conduction mechanism, and the density of states near Fermi level have been calculated. The difference in electrical response due to different substitutions in the glassy matrix is analyzed.

Nonlinear optical properties of IV-V-VI chalcogenide glasses

Se based glasses are suitable optical materials and may be used for high speed communication fibers. Third order nonlinear susceptibility has been evaluated from changing refractive index using Wang approximations. Nonlinear behavior of Ge19Se81−xSbx (where x = 0, 4, 8, 12, 16, 17.2, 20) has been predicted using suitable relation between linear refractive index and nonlinear refractive index.

A Study of Thermal Stability And Crystallization Kinetics of SbSeGe Glassy Alloys

Alloys of Sb10Se90-xGex (x = 0, 19, 21, 23, 25, 27) have been prepared using melt quenching technique. Differential thermal analysis has been used to determine the three characteristic temperatures, glass transition (Tg), glass crystallization (Tc) and melting temperature (Tm), at four heating rates 5, 10, 15 and 20 K/min. The thermal stability and ease of glass formation have been evaluated in terms of Hruby parameter and reduced glass transition temperature respectively. The activation energy for glass crystallization (Ec) has been calculated using Kissingers method and Marseglia theory. The composition dependence of Tg and Ec has also been discussed.

SbSeGe semiconducting alloys: Non-linear refractive index and susceptibility

Third order non-linear optical properties are of great interest because of their potential applications in telecommunication devices. Third order non-linear susceptibility (χ(3)) and non-linear refractive index (n2) of SbSeGe glassy alloys have been calculated using linear refractive index and Wemple DiDomenico parameters. The values of χ(3) and n2 decrease as Ge concentration increases in the Sb10Se90 system.

Stability analysis of IV-V-VI chalcogenide glasses using glass transition and crystallization temperature

Selenium based chalcogenide glasses are attractive candidates for IR devices due to their low transmission loss. Thermal studies for Ge19Se81-xSbx (x = 0, 4, 8, 12, 16, 17.2, 20) have been carried out using differential thermal analysis. Glass transition temperature has been calculated using Tanakas relation. Marseglias and Ozawas methods have been used for the calculation of activation energy for crystallization. Effect of Sb addition on GeSe base system shows that resistance to devitrification increases up to x = 17.2.