UV Light-Emitting Diode With Buried Polarization- Induced n-AlGaN/InGaN/p-AlGaN Tunneling Junction

The polarization-induced electric field in the III-nitride UV light-emitting diode (LED) allows for significant flexibility in device design to address the electron overflow and hole injection issues. The conventional AlGaN-based UV LED with the PIN structure suffers from insufficient carriers especially hole concentration due to the large valence band barrier for hole injection and p-type doping challenge. Our systematic study reveals that the inverse design of the n-type and p-type layer shall build an opposite polarization-induced field to suppress electron overflow as well as simultaneously enhance hole injection. To design this p-side down UV LED and improve the hole injection, we adopt the n-AlGaN/i-InGaN/p-AlGaN buried tunneling junction (BTJ) instead of the bottom p-layer. The tunneling probability and output power of the LED are further investigated by optimizing the composition and thickness of the InGaN layer. Simulation results show that the optimized 3 nm In0.3Ga0.7N tunneling layer could lead to several orders of magnitude enhancement for LED output power. This study is significant for the pursuit of highly efficient UV LEDs.

Automated summary

The study demonstrates the importance of inverse design of n-type and p-type layers in generating opposite polarization-induced fields to suppress electron overflow and enhance hole injection in III-nitride UV LEDs. By utilizing a buried tunneling junction (BTJ) composed of n-AlGaN/i-InGaN/p-AlGaN, significant enhancement in LED output power can be achieved through optimizing the composition and thickness of the InGaN tunneling layer.