2D ferroelectric narrow-bandgap semiconductor Wurtzite' type α-In₂Se₃ and its silicon-compatible growth.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) van der Waals ferroelectrics are crucial for next-generation information storage.
• Alpha-indium selenide ($\alpha$-In$_2$Se$_3$) is a promising candidate due to its band gap and ferroelectricity.
• Challenges exist in experimentally validating and synthesizing the wurtzite phase of $\alpha$-In$_2$Se$_3$.

Purpose of the Study:

• To report the in-situ transport growth of centimeter-scale wurtzite type $\alpha$-In$_2$Se$_3$ films.
• To characterize the material properties of wurtzite $\alpha$-In$_2$Se$_3$ for potential applications.
• To demonstrate the material's utility in neuromorphic computing devices.

Main Methods:

• In-situ transport growth combining pulsed laser deposition and chemical vapor deposition.
• Synthesis of centimeter-scale wurtzite type $\alpha$-In$_2$Se$_3$ films on SiO$_2$ substrates.
• Characterization of ferroelectric, electronic, and optical properties.

Main Results:

• Successfully synthesized centimeter-scale wurtzite $\alpha$-In$_2$Se$_3$ films.
• Demonstrated a narrow bandgap ferroelectric semiconductor with a Curie temperature > 620 K.
• Achieved a tunable bandgap (0.8–1.6 eV) and high optical absorption (1.3 × 10^6/cm).
• Showcased enhanced synapse device performance for neuromorphic computing with 92.3% recognition accuracy.

Conclusions:

• Established ferroelectric polymorphism in $\alpha$-In$_2$Se$_3$ with the validation of the wurtzite phase.
• Highlighted the potential of wurtzite $\alpha$-In$_2$Se$_3$ in ferroelectric synapses for neuromorphic computing.
• Confirmed the material's suitability for advanced information storage technologies.