Miniaturized and high efficient GaN-based blue micro-LEDs for future display applications

To design an ultra-small blue micro light emitting diode μ-LED (< 5 μm) with high light extraction efficiency is one of the bottlenecks currently. How the extraction efficiency can be boost of a very small sized μLED is taking the attention of most of the researchers. As the surface-to-volume ratio of μLEDs is much larger than traditional LEDs. We designed and developed a miniaturized GaN-based vertical blue μLED and conduct a systematic research by simulating the structure in finite-difference-time-domain (FDTD). We develop a miniaturized state of the art blue μ-LED (GaN) which exhibits high light extraction efficiency of 70.4% having the size of 1 μm × 1 μm. The μ-LED is backed by multi distributed Bragg reflector to achieve the high extraction efficiency, M-DBR consists layers of Ti3O5 and SiO2. During investigating the proposed μLED design we derived that the light extraction efficiency (LEE) has a strong dependency on some of the structural parameters of μ-LED i.e. thickness of each layers specifically MQW, μ-LED chip size, chip shape, orientation and position of the dipole source. The proposed GaN-based blue μ-LED structure is evaluated, simulated and optimized for different dipole orientation and positions with different chip sizes and shapes. At end come up with the smallest and most optimized vertical blue μ-LED structure for future display applications.