Directional solidification of a Sn-Se eutectic alloy using the Bridgman-Stockbarger method

A Sn-Se eutectic alloy was directionally solidified at growth rates of 0.47, 1.54, 1.65, 2.03, and 3.07 cm/h in a vertical Bridgman-Stockbarger furnace. Such eutectic growth allows one to obtain a lamellar structure formed by SnSe and SnSe2 solid phases, which are p and n semiconducting type, respectively. The main goal of this work was to evaluate the eutectic microstructure behavior as a function of changes in directional solidification parameters. To analyze the influence of forced convection on eutectic growth, ampoule rotation (150 rpm) was applied when the sample translation was 1.65 cm/h. The results obtained show that the eutectic lamellar spacings depend on the growth rate and the presence of convection in the liquid phase. Also, a relationship between lamellar spacing and growth rate was found.