Crystalline-crystalline phase transformation in two-dimensional In2Se3 thin layers

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Indium selenide (In2Se3) is a promising semiconductor material.
• Understanding phase transitions in thin films is crucial for device applications.
• Mechanical exfoliation is a key technique for producing high-quality 2D materials.

Purpose of the Study:

• To fabricate single-crystal In2Se3 thin layers.
• To investigate the crystalline-crystalline (alpha to beta) phase transformations.
• To study the impact of these transformations on electrical properties.

Main Methods:

• Mechanical exfoliation of In2Se3.
• Electron microscopy for structural analysis.
• In situ micro-Raman spectroscopy and electrical measurements.

Main Results:

• Single-crystal In2Se3 thin layers were successfully fabricated.
• The beta phase of In2Se3 can persist at room temperature in thin layers, unlike in bulk.
• Electrical resistivity of the beta phase is 1-2 orders of magnitude lower than the alpha phase.
• Phase transformation temperature increases with decreasing layer thickness.

Conclusions:

• Single-crystal In2Se3 thin layers exhibit unique phase behavior.
• The beta phase's stability at room temperature is significant for electronic applications.
• These findings pave the way for developing novel multilevel phase-change memory devices using In2Se3.