Preparation and characterization of amorphous cadmium–selenium ribbons

Chalcogenide glasses based on the cadmium–selenium system, with the selenium composition varying from 0 to 7.5 wt% have been prepared using melt-quenching method i.e., single-roller quenching technique. The X-ray diffraction (XRD) and selected area electron diffraction (SAD) patterns of the CdSe ribbons indicate that the ribbons are amorphous. The transmission electron microscopy (TEM) studies carried out on these ribbons reveal that the constituents are inhomogeneously distributed in these ribbons. The temperature dependence of the electrical resistivity, ρ and thermoelectric power (TEP) of these ribbons has been studied in the temperature range 30–350 °C. The sudden jump in the values of electrical resistivity at a specific temperature for each case in these ribbons has been correlated with the phase transition i.e., the onset of crystallization in these materials during heating. The crystallization temperature, T_c has been found to be a function of Se content of these ribbons. The phase change in these ribbons as a result of heating does not seem to affect the variation of TEP with temperature. However, the slope of TEP versus temperature curves depends on Se content in these ribbons. The differential scanning calorimetry (DSC) of these ribbons indicates that the supercooled region in these ribbons extends from 50 to 70 °C. The composition CdSe ribbon with 0.5 wt% Se has the highest value of T_c and glass forming ability, K_g = 0.7.