Vertical InGaN Light-Emitting Diode with Hybrid Distributed Bragg Reflectors.

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Physics

Background:

• Vertical-type InGaN LEDs are crucial for various lighting and display applications.
• Achieving efficient light extraction and directional emission in LEDs remains a challenge.
• Resonant cavities and advanced reflector structures are key to improving LED performance.

Purpose of the Study:

• To demonstrate a vertical-type InGaN LED with a resonant cavity using hybrid distributed Bragg reflectors (DBRs).
• To investigate the impact of a porous-GaN DBR structure on LED performance.
• To explore the potential for directional emission and vertical-cavity surface-emitting diode laser applications.

Main Methods:

• Fabrication of a vertical-type InGaN LED with a 9 μm aperture and a short cavity.
• Design of epitaxial structures and use of electrochemical etching to create porous GaN DBRs.
• Employing a laser lift-off process for free-standing membrane fabrication and DBR inversion.

Main Results:

• A hybrid DBR structure combining porous GaN and dielectric layers was successfully implemented.
• The resonant cavity significantly reduced the physical cavity length to 0.74 μm.
• Emission characteristics improved dramatically, with divergent angles reduced from 124° to 44° and line width narrowed to 3.3 nm.

Conclusions:

• The developed membrane-type LED with hybrid DBRs exhibits excellent vertical current injection and improved optical properties.
• The device shows significant potential for directional light sources.
• This technology could be applied to vertical-cavity surface-emitting diode lasers.