Wafer-Scale Transferrable GaN Enabled by Hexagonal Boron Nitride for Flexible Light-Emitting Diode

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Van der Waals epitaxy using 2D materials is crucial for transferring high-quality III-nitride semiconductors.
• Developing wafer-scale transferrable GaN epilayers with low dislocation density is essential for advanced electronic applications.

Purpose of the Study:

• To demonstrate wafer-scale transferrable GaN epilayers using a composite buffer layer for flexible LEDs.
• To investigate the nucleation and bonding mechanisms of GaN and AlN on hexagonal boron nitride (h-BN) using first-principles calculations.
• To propose a strain-relaxation model for III-nitrides grown on h-BN.

Main Methods:

• Utilizing an Aluminum Nitride (AlN)/hexagonal Boron Nitride (h-BN) composite buffer layer for GaN epitaxy.
• Employing first-principles calculations to study GaN and AlN nucleation and bonding on h-BN.
• Applying mechanical exfoliation for transferring single-crystalline GaN films and fabricating flexible LEDs.

Main Results:

• Achieved wafer-scale transferrable GaN epilayers with low dislocation density.
• Confirmed higher adsorption energy of Al atoms on O2-plasma-treated h-BN compared to Ga atoms.
• Demonstrated flexible InGaN-based LEDs with approximately 66% luminescence enhancement and improved reliability after transfer.

Conclusions:

• Developed a novel approach for fabricating flexible semiconductor devices using III-nitrides and 2D materials.
• The AlN/h-BN composite buffer layer effectively manages strain during GaN epitaxy and transfer.
• The proposed strain-relaxation model provides insights into III-nitride growth on h-BN.