Abstract
In this study, high-performance InGaN-based green light-emitting diodes (LEDs) with a quaternary InAlGaN/GaN superlattice electron blocking layer (QSL-EBL) have been demonstrated. The band structural simulation was employed to investigate the electrostatic field and carriers distribution, show that the efficiency and droop behavior can be intensively improved by using a QSL-EBL in LEDs. The QSL-EBL structure can reduce the polarization-related electrostatic fields in the multiple quantum wells (MQWs), leading to a smoother band diagram and a more uniform carriers distribution among the quantum wells under forward bias. In comparison with green LEDs with conventional bulk-EBL structure, the light output power of LEDs with QSL-EBL was greatly enhanced by 53%. The efficiency droop shows only 30% at 100 A/cm2 comparing to its peak value, suggesting that the QSL-EBL LED is promising for future white lighting with high performance.
Highlights
In recent years, high efficiency light-emitting diodes (LEDs) have attracted intensive attentions due to their wide applications in solid-state lighting and functional display technology [1,2]
We demonstrated a quaternary superlattice electron blocking layer (QSL-EBL) design for droop improvement in green LEDs
It is worth noting that the electrostatic field at the last barrier is negative, which means that the negative field would favor holes into multiple quantum wells (MQWs)
Summary
High efficiency light-emitting diodes (LEDs) have attracted intensive attentions due to their wide applications in solid-state lighting and functional display technology [1,2]. Band diagrams of quantum wells (QWs) in green LED is more tilted than those of blue ones, and the electron and hole wave functions overlap becomes weaker [3,4,5,6], resulting in lower recombination rate and poor internal quantum efficiency (EQE). The highly-tilted band diagram leads to a serious “efficiency droop” in InGaN-based green LEDs, which has been attributed to the enhanced carrier overflow out of the active region and inefficient hole transport [8]. The band bending reduces the barrier height for electron leakage and increases the effective barrier height for hole injection, leading to a strong efficiency droop [9,10,11]. The QSL-EBL can significantly increase the potential barrier height for electrons and leads to lower effective barrier height for holes simultaneously
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
