Achieving High-Performance Blue GaN-Based Light-Emitting Diodes by Energy Band Modification on Al<italic>x</italic>In<italic>y</italic>Ga1–<italic>x</italic>–<italic>y</italic>N Electron Blocking Layer

Abstract

We have achieved high-performance blue GaN-based light-emitting diodes (LEDs) by energy band modification on an Al x In y Ga1– x – y N electron blocking layer (EBL). It is demonstrated by simulation that the strategy using high In/Al ratio to decrease polarization charge density and to alleviate the negative effect from polarization electric fields is more favorable. Using the optimal In/Al ratio of 0.5, the LED with Al0.40In0.20Ga0.40N EBL shows a comprehensive performance improvement. With comparison to the LED with conventional Al0.15GaN0.85N EBL, such an LED owns a 270.15% improvement on the simulated luminous intensity and shows the smallest voltage of 3.34 V at 100 A/cm2. The subsequent experimental results provide the evidence to the superiority of Al x In y Ga1– x – y N1– x – y N EBL with a high In/Al ratio. Compared with the reference LED with Al0.15Ga0.85N EBL, the experimental light output power of the LED with Al0.35In0.18Ga0.47N EBL is 86.58 mW, achieving the best improvement by 31.38%. And the voltage of this LED at 14.4 A/cm2 (20 mA) is 3.35 V, which is much smaller than the voltage of 3.45 V for the reference LED. Evidently, the Al x In y Ga1– x – y N EBL with the In/Al ratio of 0.5 is very effective to promote the performance of LED, which is very promising to be applied in the further high-performance LED fabrication.