UNIRED · UNderstanding and improving the efficiency of InGaN Red LEDs for micro-Display applications

Indium gallium nitride (InGaN) semiconductors have emerged as a highly promising material platform for the realization of high-performance red–green–blue (RGB) micro-light-emitting diode (μLED) displays within a single material family. However, there remains a disparity in performance, with blue InGaN LEDs demonstrating higher efficiency than their red counterparts. The problem arises from the high indium (In) content, which leads to lattice strain, defect generation, and quantum-confined Stark effect hindering the development of high-efficiency red InGaN μLEDs. UNIRED aims to investigate defect-related limitations and their suppression strategies in InGaN nanowires (NWs). Overcoming these challenges is critical to unlock full-spectrum RGB emission from a monolithic system. UNIRED addresses this bottleneck by systematically undertaking an in-depth analysis of the types and origins of defects in high-In InGaN nanostructures, their influence on optoelectronic properties, and mitigation routes to minimize non-radiative recombination losses. This comprehensive approach is designed to establish clear structure–property correlations and provide pathways to enhance red emission. The methodology combines diameter-dependent selective area molecular beam epitaxial growth with controlled In incorporation for tunable RGB emission. Axial GaN barriers, lateral GaN shell encapsulation, and a low-In buffer layer collectively suppress defects, relieve strain, and enhance the efficiency of red-emitting NW-based μLEDs. UNIRED further benchmarks the performance of its monolithic NW-based μLEDs against industrial-standard nanophosphor-based red μLEDs to provide a clear comparative framework. By pioneering this integrated strategy, UNIRED aims to overcome the efficiency limitations of red InGaN emitters, enabling true monolithic RGB integration. The outcomes will pave the way for compact, energy-efficient, and high-resolution next-generation μLED display technologies.