EXAFS study of Sb-Te alloy films

The local structures of three phases; stable compound Sb2Te3, metastable cr ystalline c-SbTe and amorphous a-SbTe films having the atomic ratio Sb/Te=3 ; in Sb-Te system have been studied by EXAFS. The c-SbTe has a partly simil ar local structure to crystalline Sb2Te3. The a-SbTe film has a local struc ture of NaCl-type, which is topologically analogous to the crystalline form . The amorphous phase has shorter bond distances 2.86 Angstrom (around Sb-s ite) and 2.83 Angstrom (around Te-site) than the corresponding distances 2. 89 Angstrom and 2.87 Angstrom in the crystalline phase. This unbalanced bon d distances between the Sb-site and Te-site implies that site-disordering o ccurs. Shortening of bond distances in the amorphous phase is due to the re laxation of locally distorted crystalline structure.