A Combined Theoretical and Experimental Raman Scattering Study of BaZrS₃-BaHfS₃ Solid Solutions

Area of Science:

• Materials Science
• Solid-State Chemistry
• Spectroscopy

Background:

• Barium zirconium hafnium sulfide (Ba(Zr,Hf)S3) solid solutions show promise for photovoltaic applications.
• Accurate, non-destructive methods for measuring composition and identifying secondary phases are essential for understanding optoelectronic properties.

Purpose of the Study:

• To investigate the use of Raman spectroscopy for determining the composition of Ba(Zr,Hf)S3 solid solutions.
• To identify a reliable method for rapid, non-destructive alloy composition measurement.

Main Methods:

• Calculation of non-resonant one-phonon Raman spectra for pure BaHfS3 and BaZrS3.
• Synthesis of BaZr1-xHfxS3 (0≤x≤1) solid solution powders.
• Raman spectroscopy with 633 nm excitation.
• X-ray diffractograms and optical absorption spectra analysis.
• Resonant Raman spectroscopy measurements.

Main Results:

• Non-resonant Raman spectra of pure BaHfS3 and BaZrS3 show subtle differences due to sulfur atom dominance and mass-bond compensation.
• Synthesized BaZr1-xHfxS3 powders were free of secondary phases.
• Non-resonant Raman measurements on alloys showed slight spectral variations, hindering composition determination.
• Resonant excitation revealed new two-phonon modes that varied significantly across the alloy series.

Conclusions:

• A rapid and unambiguous alloy composition measurement for Ba(Zr,Hf)S3 can be achieved by measuring the intensity ratio of Raman features at 825 cm-1 and 625 cm-1 using resonant excitation.