Thermal behavior of AlGaN-based deep-UV LEDs

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Physics

Background:

• Deep ultra-violet light-emitting diodes (DUV-LEDs) are crucial for various applications.
• Improving the efficiency and thermal management of DUV-LEDs remains a key challenge.
• Existing DUV-LED designs often face limitations in light extraction and operational stability.

Purpose of the Study:

• To enhance the performance of DUV-LEDs by employing thin p-GaN and indium tin oxide (ITO) layers.
• To investigate the impact of a novel reflective passivation layer (RPL) on DUV-LED efficiency and thermal characteristics.
• To analyze the trade-offs between thin film deposition and device performance metrics.

Main Methods:

• Fabrication of DUV-LEDs utilizing thin p-GaN (40 nm) and ITO (12 nm) layers.
• Deposition of HfO2/SiO2-based RPL structures to achieve high reflectance.
• Characterization of device performance, including wall-plug efficiency (WPE) and light extraction efficiency (LEE).
• Analysis of junction temperature and thermal behavior under varying injection currents.

Main Results:

• The optimized DUV-LEDs with RPL achieved a peak WPE of 2.59% and LEE of 7.57%.
• The thin p-GaN, ITO, and RPL structure demonstrated improved thermal management, with lower junction temperatures at high currents compared to reference devices.
• Temperature-sensitive coefficients (dV/dT, dLOP/dT, dWLP/dT) were favorably influenced by the thin film and RPL integration.

Conclusions:

• The integration of thin p-GaN, ITO, and RPL is an effective strategy for boosting DUV-LED performance.
• RPL significantly enhances light extraction and wall-plug efficiency.
• Improved thermal management achieved with thin films and RPL contributes to better device stability and operational characteristics.