Performance improvement of AlGaN-based deep ultraviolet light-emitting diodes with double electron blocking layers

Abstract

The AlGaN-based deep ultraviolet light-emitting diodes (LED) with double electron blocking layers (d-EBLs) on both sides of the active region are investigated theoretically. They possess many excellent performances compared with the conventional structure with only a single electron blocking layer, such as a higher recombination rate, improved light output power and internal quantum efficiency (IQE). The reasons can be concluded as follows. On the one hand, the weakened electrostatic field within the quantum wells (QWs) enhances the electron–hole spatial overlap in QWs, and therefore increases the probability of radioactive recombination. On the other hand, the added n-AlGaN layer can not only prevent holes from overflowing into the n-side region but also act as another electron source, providing more electrons.

Optimization of AlGaN-Based Deep Ultraviolet Laser Diodes with Graded Rectangular Superlattice Electron Blocking Layer and Graded Trapezoidal Superlattice Hole Blocking Layer

“…Meanwhile, there will be a large number of carriers that have not recombined with each other successfully [25]. The carriers escaping from QWs leak into the p-type and n-type regions, which will negatively affect the performance of the device [26]. Therefore, higher carrier injection and lower carrier leakage mean better carrier confinement capability and performance of devices [27].…”

Enhancing the Luminous Efficiency of Ultraviolet Light Emitting Diodes By Adjusting the Al Composition of Pre-Well Superlattice

“…It is well known that the polarization-induced electric field between the last quantum barrier layer (LQB) in MQWs and the p-type layer lowers the energy band at the interface, causing electrons to leak into the p-type, thereby participating in non-radiative recombination [10]. Various approaches, such as employing high Al composition AlGaN electron blocking layer (EBL) [11], graded EBL [12], insertion layer in EBL [13], and multi-quantum barriers EBL [14], have been put forward to cope with this problem. Besides, lowering the dislocation density is as well considered a working way to maximize luminous efficiency.…”

Efficiency Improvement of Deep‐Ultraviolet Light Emitting Diodes with Gradient Electron Blocking Layers

“…This result proved that the study of EBL variation can make a breakthrough in efficiency improvement in AlGaN‐based DUV‐LEDs. Although many reports demonstrated enhanced DUV‐LED simulation results through EBL modification, practical devices were reported in only a few papers . Simulation studies of the insertion of gradient EBLs (GEBLs) have been attempted by some groups.…”