High-performance AlGaN-based deep ultraviolet light-emitting diodes with different types of InAlGaN/AlGaN electron blocking layer

The efficiency performance of AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) is restricted by the poor hole injection and severe electron leakage. Here, we propose two types of electron blocking layer (EBL), including InAlGaN/AlGaN EBL and InAlGaN/AlGaN superlattice EBL, to enhance the carrier injection efficiency. We numerically simulated the effect of InAlGaN-based EBL on effective barrier height for carriers. The simulation results reveal that the effective barrier height for carriers can be modulated to be beneficial for electron blocking and hole injection by optimizing In-composition. As a result, the 272 nm DUV LED with InAlGaN/AlGaN EBL exhibits better performance, compared to the DUV LED with AlGaN EBL. What is more, device performance can be further improved when the InAlGaN/AlGaN EBL is replaced by InAlGaN/AlGaN superlattice EBL, due to the latter is more effective to modulate the effective barrier height for carriers when the In-composition is appropriate.