High pressure orthorhombic structure of CuInSe2

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Copper indium diselenide (CuInSe2) is a semiconductor with potential applications in photovoltaics.
• Understanding its structural behavior under extreme conditions is crucial for material design.
• Previous studies indicated a phase transition at 7.6 GPa.

Purpose of the Study:

• To investigate the structural response of CuInSe2 to high pressure up to 53 GPa.
• To confirm and further characterize the high-pressure phases of CuInSe2.
• To elucidate the sequence of structural transformations under compression.

Main Methods:

• Angle-dispersive X-ray powder diffraction was employed.
• High pressure was generated using diamond anvil cells.
• Diffraction patterns were analyzed to determine crystal structures and lattice parameters.

Main Results:

• The previously reported tetragonal to NaCl-like cubic phase transition at 7.6 GPa was confirmed.
• A new structural phase transition was observed at 39 GPa.
• The high-pressure phase at 53 GPa was identified as orthorhombic (Cmcm) with specific lattice parameters.

Conclusions:

• CuInSe2 exhibits complex structural phase transitions under high pressure.
• The observed phase transitions are consistent with trends in similar semiconductor materials.
• The orthorhombic Cmcm phase represents a distorted form of the cubic NaCl-type structure.