EXAFS study of Sb-Te alloy films

The local structures of three phases; stable compound Sb₂Te₃, metastable crystalline 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 similar local structure to crystalline Sb₂Te₃. The a-SbTe film has a local structure of NaCl-type, which is topologically analogous to the crystalline form. The amorphous phase has shorter bond distances 2.86 Å (around Sb-site) and 2.83 Å (around Te-site) than the corresponding distances 2.89 Å and 2.87 Å in the crystalline phase. This unbalanced bond distances between the Sb-site and Te-site implies that site-disordering occurs. Shortening of bond distances in the amorphous phase is due to the relaxation of locally distorted crystalline structure.