EXAFS study of Sb-Te alloy films

Area of Science:

• Materials Science
• Solid State Physics
• Condensed Matter Physics

Background:

• The Sb-Te system is crucial for thermoelectric materials.
• Understanding local atomic structures is key to material properties.

Purpose of the Study:

• To investigate the local atomic structures of stable crystalline Sb2Te3, metastable crystalline c-SbTe, and amorphous a-SbTe films.
• To compare the structural differences between crystalline and amorphous Sb-Te phases.

Main Methods:

• Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was employed.
• Analysis focused on Sb-site and Te-site local environments.

Main Results:

• Amorphous a-SbTe displays an NaCl-type local structure, topologically similar to crystalline forms.
• Shorter bond distances (Sb-site: 2.86Å, Te-site: 2.83Å) were observed in amorphous films compared to crystalline phases (Sb-site: 2.89Å, Te-site: 2.87Å).
• Unbalanced bond distances indicate site-disordering in the amorphous phase.

Conclusions:

• The amorphous Sb-Te phase exhibits significant structural differences from its crystalline counterparts.
• Shorter bond lengths in amorphous Sb-Te are attributed to the relaxation of locally distorted crystalline structures.
• Site-disordering is a key characteristic of the amorphous Sb-Te local structure.