EBL-free strategic hybrid MQW with indium-alloyed barriers for efficient green micro-LEDs with reduced operating voltage

Abstract Green micro-light emitting diodes ( µ LEDs) with sub-100 µ m dimensions are crucial for next-generation display technologies but remain constrained by the persistent ‘green gap’ and low current density operation challenges. This work numerically investigates optimized epitaxial designs for 60 × 60 µ m 2 InGaN-based green µ LEDs operating at 1 A cm −2 , exploring multiple configurations to reveal performance enhancing innovations and their underlying mechanisms. We propose a hybrid multiple quantum well design featuring four step-graded low-indium-content passive quantum wells paired with a single green emitting active QW. This configuration enhances electron–hole wavefunction overlap, suppresses the quantum confined Stark effect, and reduces the active recombination volume. Further performance improvements are achieved by eliminating the electron blocking layer to boost hole injection and introducing indium-alloyed quantum barriers to reduce polarization-induced interface charges. These innovations collectively result in an 18% increase in internal quantum efficiency, a 37% reduction in operating voltage, and a 74% enhancement in wall-plug efficiency compared to the conventional high-indium-content identical 5-QW structure. This simplified final design offers a scalable and cost-effective pathway toward high-efficiency green µ LEDs, with implications for broader adoption in full-color micro-displays and long-wavelength III-Nitride emitters.