Performance enhancement of AlGaN-based ultraviolet light-emitting diodes by tailoring polarization in electron blocking layer

• AlGaN UV LEDs with specific EBL have been designed.
• 2-D simulation physical models are used to simulate the performance of UV LEDs.
• Polarization-induced p-type doping has important effect on hole injection efficiency.
• The designed UV LED shows improved performance compared with conventional LED.

The AlGaN-based ultraviolet light-emitting diodes (UV LEDs) with specific design of graded AlGaN electron blocking layer (EBL) are investigated numerically. The light output power of LEDs with tailored graded AlGaN EBL is markedly improved. Simulation analysis shows that via proper modification of polarization field from the last barrier of the active region to EBL, not only the elimination of electron overflow to p-type layer can be achieved, but also the hole injection into the active region can be enhanced. The enhanced performance for tailored UV LED is explained by the simulated energy band diagrams, distribution of carrier concentration and radiative recombination rate in the quantum wells.