Excitonic and electronic transitions in Me-Sb₂Se₃ structures

Area of Science:

• Solid State Physics
• Materials Science
• Optoelectronics

Background:

• Antimony triselenide (Sb₂Se₃) is a promising material for optoelectronic applications.
• Understanding its optical anisotropy and electronic band structure is crucial for device optimization.
• Excitonic properties significantly influence the optical response of semiconductors.

Purpose of the Study:

• To investigate the optical anisotropy of Sb₂Se₃ crystals at different temperatures.
• To identify and characterize excitonic features in Sb₂Se₃.
• To determine key electronic parameters, including effective masses and band splitting.

Main Methods:

• Optical spectroscopy was performed on Sb₂Se₃ single crystals at 300 K and 11 K.
• Photoelectric spectra of metal-semiconductor (Me-Sb₂Se₃) structures were analyzed.
• Theoretical calculations of energy band structure and excitonic symmetry were employed.

Main Results:

• Four distinct excitonic features (A, B, C, D) were observed and characterized.
• Ground and excited state exciton positions and binding energies were determined.
• Effective masses for electrons and holes, along with valence band splittings due to spin-orbit and crystal field interactions, were calculated.

Conclusions:

• The observed excitonic features are consistent with the orthorhombic crystal structure (Pnma) of Sb₂Se₃.
• Detailed electronic parameters provide insights into the charge transport properties of Sb₂Se₃.
• The study establishes a foundation for further exploration of Sb₂Se₃ in advanced electronic and photonic devices.