In-situ XAFS studies on local structures of molten InSb compounds

Abstract

The local structures of semiconductor InSb compound have been studied by in-situ XAFS in the temperature range of 300 and 823 K. Reverse Monte Carlo calculation is used to simultaneously fit both In and Sb K-edge EXAFS functions kχ(k) of InSb compound. The fitting results indicate that the average bond length R1 (2.80 Å) and the average coordination number N1 (4.0) of the first In-Sb (or Sb-In) shell of InSb (723 K) are similar to those (2.79 Å, 4.0) of crystalline InSb (300 K) with a zinc-blende structure, in spite of InSb compound possessing a large thermal disorder degree at 723 K. At the temperature of 828 K (Tm(InSb) = 798 K), the R1 and N1 of the first In-Sb shell are 2.90 Å and 5.8, and the R1 and N1 of the first Sb-In shell are 2.90 Å, and 5.5 for molten InSb, respectively. For molten InSb (828 K), the coordination numbers of the In-Sb (or Sb-In) first shell are mostly 5 and 6, and a few percent of In-In (or Sb-Sb) coordination appears in the first shell. It implies that the tetrahedron structures of the In-Sb (or Sb-In) covalent bonds of InSb compound have been destroyed in the liquid state.