Electrically Switchable Polarization in Bi₂ O₂ Se Ferroelectric Semiconductors.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Atomically 2D layered ferroelectric semiconductors enable simplified electronic components and high-density integration.
• Bismuth oxychalcogenides (Bi2O2Se) are explored as a room-temperature 2D ferroelectric semiconductor material.

Purpose of the Study:

• Investigate the properties of ultrathin (down to 7.3 nm) 2D Bi2O2Se.
• Uncover the relationship between ferroelectricity and semiconducting characteristics in Bi2O2Se devices.
• Demonstrate the potential for integrating multiple functions into a single material system.

Main Methods:

• Fabrication and characterization of ultrathin Bi2O2Se films.
• Electrical measurements to probe ferroelectric polarization and semiconducting behavior.
• Device-level operation analysis including photoresponse and memory characteristics.

Main Results:

• Bi2O2Se exhibits a piezoelectric coefficient (d33) of 4.4 ± 0.1 pm V⁻¹ at room temperature.
• Hysteresis behavior and memory window (MW) formation were observed, with a large MW of 47% at VGS = ±5 V.
• The device showed tunable photoresponse and a high on/off current ratio > 10⁴.

Conclusions:

• Bi2O2Se demonstrates a synergistic combination of ferroelectric and semiconducting properties.
• This material platform supports the integration of sensing, logic, and memory functions.
• Findings pave the way for overcoming bottlenecks in von Neumann architecture.