High-performance electron-blocking-layer-free deep ultraviolet light-emitting diodes implementing a
Optics Letters
|September 15, 2020
Summary
This study introduces electron-blocking-layer (EBL)-free AlGaN ultraviolet (UV) LEDs with a novel strip-in-a-barrier structure. The innovative design significantly boosts optical power and internal quantum efficiency while reducing efficiency droop.
Area of Science:
- Semiconductor Physics
- Optoelectronics
- Materials Science
Background:
- Conventional AlGaN ultraviolet (UV) light-emitting diodes (LEDs) often suffer from electron leakage and poor hole injection, limiting their efficiency.
- Electron-blocking layers (EBLs) are typically used to mitigate these issues but can introduce additional complexities and performance limitations.
Purpose of the Study:
- To propose and investigate an electron-blocking-layer (EBL)-free AlGaN ultraviolet (UV) LED structure utilizing a novel strip-in-a-barrier design.
- To enhance carrier radiative recombination, reduce electron leakage, and improve optical power and internal quantum efficiency (IQE) in UV LEDs.
Main Methods:
- Systematic engineering of quantum barrier (QB) structures by integrating a 1 nm intrinsic AlxGa(1-x)N strip into the middle of QBs.
- Fabrication and characterization of EBL-free AlGaN UV LEDs with the proposed strip-in-a-barrier structure.
- Comparison of performance metrics (radiative recombination, electron leakage, optical power, IQE, IQE droop) against conventional AlGaN EBL LED structures.
Main Results:
- The proposed strip-in-a-barrier structure significantly reduces electron leakage by approximately 11 times.
- Radiative recombination is improved by about 220%, and optical power is enhanced by about 225% at 60 mA compared to conventional EBL LEDs.
- The EBL-free UV LED achieved a maximum internal quantum efficiency (IQE) of ~61.5% (72% higher) and a reduced IQE droop of ~12.4% (333% less).
Conclusions:
- The EBL-free AlGaN UV LED with the strip-in-a-barrier structure demonstrates a promising approach to overcome the limitations of conventional designs.
- This innovative structure offers a potential solution for enhancing optical power and achieving highly efficient UV emitters.
- The results highlight the effectiveness of integrating intrinsic AlxGa(1-x)N strips within quantum barriers for improved UV LED performance.
