GaN-Based Resonant-Cavity Light-Emitting Diodes Grown on Si

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Devices

Background:

• Gallium nitride (GaN)-based light-emitting diodes (LEDs) are crucial for optoelectronic applications.
• Integrating GaN with silicon (Si) substrates offers a pathway to cost-effective manufacturing.
• Resonant-cavity structures enhance LED performance and spectral characteristics.

Purpose of the Study:

• To fabricate GaN-on-Si resonant-cavity light-emitting diodes (RCLEDs).
• To evaluate the performance of these RCLEDs for visible light communication (VLC) applications.
• To demonstrate the feasibility of using wafer bonding and Si substrate removal for GaN-on-Si integration.

Main Methods:

• Fabrication of GaN-on-Si RCLEDs using wafer bonding and silicon substrate removal.
• Surface preparation using chemical mechanical polishing (CMP) to achieve nanoscale roughness (0.24 nm over 5 μm × 5 μm).
• Integration of double-sided dielectric distributed Bragg reflectors (DBRs) to form a high-quality optical resonant cavity.

Main Results:

• Achieved a surface roughness of approximately 0.24 nm, crucial for high-quality DBR mirrors.
• Demonstrated a narrow cavity mode linewidth of 1 nm at a peak wavelength of ~405 nm, yielding a quality factor of 405.
• Exhibited high data transmission rates of 150 Mbps in free space, with an open eye diagram, limited by the detection system.

Conclusions:

• GaN-on-Si RCLEDs can be successfully fabricated using wafer bonding and Si substrate removal.
• The developed RCLEDs exhibit excellent optical properties and high data transmission capabilities.
• GaN-based RCLEDs on silicon are a promising low-cost emitter solution for future visible light communication systems.