Achieving High-Performance Blue GaN-Based Light-Emitting Diodes by Energy Band Modification on AlxInyGa1–x–yN Electron Blocking Layer
We have achieved high-performance blue GaN-based light-emitting diodes (LEDs) by energy band modification on an Al x In y Ga 1– 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 Al 0.40 In 0.20 Ga 0.40 N EBL shows a comprehensive performance improvement. With comparison to the LED with conventional Al 0.15 GaN 0.85 N 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/cm 2 . The subsequent experimental results provide the evidence to the superiority of Al x In y Ga 1– x – y N 1– x – y N EBL with a high In/Al ratio. Compared with the reference LED with Al 0.15 Ga 0.85 N EBL, the experimental light output power of the LED with Al 0.35 In 0.18 Ga 0.47 N EBL is 86.58 mW, achieving the best improvement by 31.38%. And the voltage of this LED at 14.4 A/cm 2 (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 Ga 1– 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.