Direct vapour transport grown Cu₂SnS₃ crystals: exploring structural, elastic, optical, and electronic properties

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Research

Background:

• Copper tin sulfide (Cu₂SnS₃) is a promising non-toxic material for photovoltaic, thermoelectric, and electrochemical applications.
• Its tunable properties and ease of synthesis make it an attractive alternative to conventional semiconductors.

Purpose of the Study:

• To synthesize Cu₂SnS₃ crystals using direct vapor transport.
• To comprehensively investigate the structural, electronic, elastic, optical, and thermal properties of Cu₂SnS₃.

Main Methods:

• Direct vapor transport for crystal growth.
• X-ray diffraction (XRD) for structural analysis.
• X-ray photoelectron spectroscopy (XPS) for composition and binding energies.
• Diffuse reflectance spectroscopy (DRS) for bandgap determination.
• Density functional theory (DFT) for property calculations.

Main Results:

• Cubic unit cell structure (a=b=c=5.403 Å) confirmed by XRD.
• XPS verified the presence of Cu¹⁺, Sn⁴⁺, and S²⁻.
• Experimental bandgap of 1.23 eV (DRS) and theoretical bandgap of 1.2 eV (DFT).
• DFT revealed temperature-dependent elastic properties, showing stability up to 953 K.
• Detailed analysis of dielectric, optical, and electronic properties.

Conclusions:

• Cu₂SnS₃ is a stable, non-toxic semiconductor with a suitable bandgap for advanced applications.
• The study provides a comprehensive understanding of its fundamental properties, facilitating further material development.
• DFT calculations offer valuable insights into its behavior under various conditions.