Local structure of amorphous tellurium studied by EXAFS

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Tellurium (Te) exists in various forms, including trigonal (t-Te) and amorphous (a-Te).
• Understanding the local structure of amorphous materials is crucial for predicting their properties.

Purpose of the Study:

• To investigate the local atomic structure of amorphous tellurium (a-Te) films.
• To compare the structural parameters of a-Te with trigonal tellurium (t-Te).

Main Methods:

• Extended X-ray Absorption Fine-Structure (EXAFS) analysis was employed.
• EXAFS data was used to determine bond lengths, coordination numbers, and Debye-Waller factors.

Main Results:

• A decrease in covalent bond length was observed in a-Te compared to t-Te.
• The Debye-Waller factor for intra-chain bonds decreased, suggesting reduced atomic vibrations.
• Inter-chain interactions were found to weaken in a-Te, while the intra-chain coordination number remained similar to t-Te.

Conclusions:

• The primary chain structure of tellurium is preserved in the amorphous state.
• The secondary structure, involving inter-chain interactions, is disrupted in a-Te.
• Weakened inter-chain interactions lead to strengthened intra-chain interactions in amorphous tellurium.