Engineering GaN-based insertion layers for high-performance green micro-LEDs: Improving carrier transport and reducing efficiency droop

Conventional green micro-LEDs ([Formula: see text]LEDs) typically incorporate an electron blocking layer (EBL) to suppress electron leakage; however, this also impedes hole injection into the active region, limiting internal quantum efficiency (IQE). To overcome this challenge, this study explores the impact of GaN, InGaN and AlGaN insertion layers (ILs) on improving carrier transport and device performance in [Formula: see text]m 2 green [Formula: see text]LEDs. The incorporation of ILs enhances the negative polarization-induced electric field, leading to hole accumulation at the EBL/IL interface, which facilitates thermionic emission, enabling more efficient hole injection into the active region. Among the investigated structures, the AlGaN-IL demonstrates the most effective carrier management, resulting in higher hole injection, reduced electron leakage and superior IQE compared to the InGaN-IL and GaN-IL counterparts. As a result, the peak IQE is improved from 24% (without IL) to 66% (AlGaN-IL), while the droop in efficiency is lowered from 63% to 40%. Additionally, the output Power density increases from 48[Formula: see text]W/cm 2 to 224[Formula: see text]W/cm 2 at 240[Formula: see text]A/cm 2 , further confirming the enhanced optoelectronic performance. This approach offers a promising strategy for enhancing the efficiency of green [Formula: see text]LEDs, paving the way for advancements in next-generation display and lighting technologies.