Robust room-temperature ferroelectricity in the wide-bandgap semiconductor Ga₂O₃

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Integrating power handling and nonvolatile memory is hindered by semiconductor and ferroelectric material incompatibility.
• Wide-bandgap semiconductors and ferroelectric materials have traditionally been incompatible.

Purpose of the Study:

• To demonstrate robust room-temperature ferroelectricity in a wide-bandgap semiconductor.
• To enable monolithic integration of power and memory functionalities.

Main Methods:

• Epitaxial growth of metastable κ-Ga₂O₃ using metal-organic chemical vapor deposition.
• Characterization using piezoresponse force microscopy, polarization hysteresis measurements, and positive up-negative down tests.
• Fabrication and testing of ferroelectric tunnel junctions.

Main Results:

• Demonstrated robust room-temperature ferroelectricity in epitaxial metastable κ-Ga₂O₃.
• Confirmed stable ferroelectric switching down to 5-nanometer thickness.
• Achieved giant tunneling electroresistance exceeding 10⁵ in ferroelectric tunnel junctions.
• Identified a unique octahedral-tetrahedral transformation enabling ferroelectricity.

Conclusions:

• κ-Ga₂O₃ is an intrinsically ferroelectric wide-bandgap semiconductor.
• This discovery challenges conventional materials paradigms.
• Enables monolithic integration of power and memory on a unified platform.