Microgravity Diffusion Experiments for Compound Semiconductor Lead-Tin-Telluride Melt in Space Shuttle Mission MSL-1

Abstract

To obtain the temperature dependence of the diffusion coefficient for Pb0.75Sn0.25Te, diffusion experiments were conducted during space shuttle mission MSL-1, launched in April and July 1997. The diffusion coefficient were measured from 1223 K to 1573 K with a diffusion couple of Pb0.8Sn0.2Te and Pb0.7Sno.3Te under controlled cooling to avoid having segregation influence solidification. MSL-1 data was much smaller than ground data, particularly at high temperature, even though almost the same value was obtained near the melting point. Temperature dependence was determined from the MSL-1 experiment as (6.7 x 10- 9 m2/ s) x (Tl Tm) 2· 6 , Tm is the melting point.