Room-temperature ferroelectricity and a switchable diode effect in two-dimensional α-In₂Se₃ thin layers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Room-temperature ferroelectricity is crucial for non-volatile memory, but conventional materials face critical thickness limitations.
• Two-dimensional (2D) van der Waals materials offer potential for ultra-thin ferroelectric applications due to their unique structures.

Purpose of the Study:

• To demonstrate a switchable room-temperature ferroelectric diode using an ultra-thin 2D ferroelectric material.
• To overcome the critical thickness effect in ferroelectric thin films for nanoelectronic applications.

Main Methods:

• Fabrication of a graphene/α-In2Se3 heterojunction utilizing a 5 nm thick 2D α-In2Se3 layer.
• Characterization of the intrinsic out-of-plane ferroelectricity of α-In2Se3 thin layers.
• Investigation of the switchable diode effect by tuning the Schottky barrier via electric polarization.

Main Results:

• Observation of reversible spontaneous electric polarization in 5 nm α-In2Se3 with a low coercive field (∼2 × 10^5 V cm-1).
• Demonstration of a switchable double diode effect in the graphene/α-In2Se3 heterojunction with a high on/off ratio (∼10^5).
• Effective tuning of the Schottky barrier by switching the ferroelectric polarization.

Conclusions:

• Ultra-thin 2D α-In2Se3 exhibits robust room-temperature ferroelectricity, overcoming critical thickness limitations.
• The demonstrated ferroelectric diode shows significant potential for novel nanoelectronic devices and high-density memory applications.