In-Composition Graded Quantum Barriers for Polarization Manipulation in InGaN-Based Yellow Light-Emitting Diodes

Area of Science:

• Materials Science
• Optoelectronics
• Solid State Physics

Background:

• Indium gallium nitride (InGaN)-based yellow light-emitting diodes (LEDs) are crucial for advanced displays and lighting.
• Achieving high efficiency and low efficiency droop in these LEDs remains a significant challenge.

Purpose of the Study:

• To investigate the impact of engineered InGaN quantum barriers (QBs) on the performance of yellow LEDs.
• To explore novel QB structures for improved electron confinement and reduced polarization effects.

Main Methods:

• Simulated three types of InGaN QBs: linear-increase (LIQB), linear-decrease (LDQB), and flat (FQB).
• Analyzed electron confinement, polarization field suppression, and radiative recombination rates.
• Evaluated efficiency droop and wavelength blueshift under varying current densities.

Main Results:

• The LIQB structure demonstrated superior electron confinement and polarization field suppression compared to LDQB and FQB.
• LEDs with LIQBs showed a reduced efficiency droop ratio (51.5%) at 100 A/cm² compared to FQBs (58.7%) and LDQBs (62.2%).
• LIQBs resulted in a smaller blueshift in peak emission wavelength (13.0 nm) over a current density range of 1-60 A/cm² compared to FQBs (14.4 nm) and LDQBs (16.5 nm).

Conclusions:

• Engineered InGaN QBs with a linear-increase In-composition offer a viable strategy for high-performance yellow LEDs.
• This approach effectively alleviates efficiency droop and improves spectral stability.
• The findings provide a pathway for developing next-generation InGaN-based LEDs in the long-wavelength region.