Three dimensional truncated-hexagonal-pyramid vertical InGaN-based white light emitting diodes based on β-Ga₂O₃

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Vertical light-emitting diodes (VLEDs) are crucial optoelectronic devices.
• Gallium Oxide (β-Ga2O3) is an emerging substrate for power electronics and optoelectronics.
• Quantum-confined Stark effect (QCSE) can limit VLED performance.

Purpose of the Study:

• To fabricate and characterize three dimensional (3D) truncated-hexagonal-pyramid (THP) VLEDs emitting white light.
• To investigate the impact of growth parameters on 3D n-GaN layer formation.
• To evaluate the performance enhancements of 3D THP VLEDs compared to planar VLEDs.

Main Methods:

• Fabrication of 3D THP VLEDs on a β-Ga2O3 substrate.
• Analysis of 3D n-GaN growth rates under varying N2 and H2 flow rates.
• Characterization of VLED performance, including internal quantum efficiency (IQE) and light extraction efficiency (LEE).
• Investigation of quantum-confined Stark effect (QCSE) suppression.

Main Results:

• Optimized growth conditions for 3D n-GaN layer with varying N2 and H2 flow rates.
• Effective suppression of QCSE in 3D THP VLEDs due to semipolar facets and strain relaxation.
• Doubled internal quantum efficiency (IQE) and significant reduction in V-shaped pits compared to planar VLEDs.
• Achieved multi-wavelength emission (448.0 nm and 498.5 nm) and improved light extraction efficiency (LEE).

Conclusions:

• 3D THP VLEDs fabricated on β-Ga2O3 exhibit superior performance.
• The unique 3D structure effectively mitigates QCSE and reduces defects.
• These findings present a promising pathway for developing high-efficiency, phosphor-free white LED devices.