Current Confinement Effect on the Performance of Blue Light Micro-LEDs with 10 μm Dimension

Abstract

The current confinement effect on the micro-LED (μLED) with a 10 μm dimension was simulated using SpeCLED software. In this study, three p-contact sizes were considered: 2 μm × 2 μm, 5 μm × 5 μm, and 8 μm × 8 μm dimensions for μLEDs with a 10 μm dimension. According to the simulation data, the highest external quantum efficiency (EQE) of 13.24% was obtained with a 5 μm × 5 μm contact size. The simulation data also showed that the μLEDs with narrow contact sizes experienced higher operating temperatures due to the current crowding effect. The experimental data revealed a red-shift effect in narrow contact sizes, indicating higher heat generation in those devices. As the contact sizes increased from 2 to 8 μm, the turn-on voltage decreased due to lower equivalent resistance. Additionally, the leakage current increased from 44 pA to 1.6 nA at a reverse voltage of −5 V. The study found that the best performance was achieved with a contact ratio of 0.5, which resulted in the highest EQE at 9.95%. This superior performance can be attributed to the better current confinement of the μLED compared to the μLED with a contact ratio of 0.8, resulting in lower leakage current and improved current spreading when compared to the μLED with a contact ratio of 0.2.