Using a Multi-Layer Stacked AlGaN/GaN Structure to Improve the Current Spreading Performance of Ultraviolet...

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Traditional ultraviolet light-emitting diodes (UVLEDs) face challenges with current spreading and defect density.
• Optimizing the n-AlGaN layer is crucial for enhancing UVLED performance.

Purpose of the Study:

• To propose and investigate a 60-period stacked Si modulation-doped n-AlGaN/u-GaN structure for improved UVLED current spreading.
• To analyze the impact of this novel structure on dislocation density, electron transport, and device efficiency.

Main Methods:

• Fabrication of UVLEDs using a stacked Si modulation-doped n-AlGaN/u-GaN structure.
• High-resolution X-ray diffraction (HRXRD) ω-scan rocking curves for structural analysis.
• Optical and electrical characterization of fabricated UVLED devices.

Main Results:

• The stacked structure effectively reduces dislocation density.
• Devices exhibit higher brightness and more uniform light emission compared to conventional UVLEDs.
• Output power and external quantum efficiency increased by 22% and 26.5% at 20 mA, respectively.

Conclusions:

• The multi-layer stacked structure alleviates current crowding by reducing dislocations, enhancing electron mobility and concentration, and weakening electron scattering.
• This approach offers a promising pathway for developing high-performance UVLEDs with superior current spreading capabilities.