Effect of temperature on effective segregation and diffusion coefficient in molten tellurium

Full text.We investigated theoretically the effect of temperature T on segregation coefficients Keff of some impurities in molten tellurium obtained by zone refining process. Pfann's model was used to determine a series of 52 values of Keff versus temperature for 13 different impurities. Keff increased with temperature for most impurities. The activation energy of the 13 impurities was also determined. This series of Keff was employed to calculate, for each impurity in tellurium molten zone, a series of 4 effective diffusion coefficients Deff. A new expression of Deff versus temperature T was demonstrated. The validity of this expression was confirmed by means of our experimental results. However, the diffusion of impurities was affected by temperature. Indeed, higher temperatures were not useful for tellurium molten zone. This work constitutes an important step toward an electronic grade purification of tellurium with good efficiency by zone refining process