Enhancement of internal quantum efficiency of green GaN-based light-emitting diodes by employing graded well/barrier/electron blocking layer

2020 ◽  
Author(s):  
Abdur-Rehman Anwar ◽  
Muhammad Usman ◽  
Munaza Munsif ◽  
Aleem Khan
Keyword(s):  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Internal Quantum Efficiency ◽  
Blocking Layer ◽  
Electron Blocking Layer ◽  
Light Emitting

scholarly journals Improved Performance of Electron Blocking Layer Free AlGaN Deep Ultraviolet Light-Emitting Diodes Using Graded Staircase Barriers

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 334
Author(s):  
Barsha Jain ◽  
Ravi Teja Velpula ◽  
Moulik Patel ◽  
Sharif Md. Sadaf ◽  
Hieu Pham Trung Nguyen
Keyword(s):  
Active Region ◽  
Light Emitting Diodes ◽  
Internal Quantum Efficiency ◽  
Hole Injection ◽  
Blocking Layer ◽  
Electron Blocking Layer ◽  
Injection Efficiency ◽  
Light Emitting ◽  
Electron Leakage ◽  
Deep Ultraviolet

To prevent electron leakage in deep ultraviolet (UV) AlGaN light-emitting diodes (LEDs), Al-rich p-type AlxGa(1−x)N electron blocking layer (EBL) has been utilized. However, the conventional EBL can mitigate the electron overflow only up to some extent and adversely, holes are depleted in the EBL due to the formation of positive sheet polarization charges at the heterointerface of the last quantum barrier (QB)/EBL. Subsequently, the hole injection efficiency of the LED is severely limited. In this regard, we propose an EBL-free AlGaN deep UV LED structure using graded staircase quantum barriers (GSQBs) instead of conventional QBs without affecting the hole injection efficiency. The reported structure exhibits significantly reduced thermal velocity and mean free path of electrons in the active region, thus greatly confines the electrons over there and tremendously decreases the electron leakage into the p-region. Moreover, such specially designed QBs reduce the quantum-confined Stark effect in the active region, thereby improves the electron and hole wavefunctions overlap. As a result, both the internal quantum efficiency and output power of the GSQB structure are ~2.13 times higher than the conventional structure at 60 mA. Importantly, our proposed structure exhibits only ~20.68% efficiency droop during 0–60 mA injection current, which is significantly lower compared to the regular structure.

Influence of the Electron Blocking Layer on the Performance of Multilayer White Organic Light-Emitting Diodes

2012 ◽  
Vol 1402 ◽  
Author(s):  
Caroline Weichsel ◽  
Sebastian Reineke ◽  
Björn Lüssem ◽  
Karl Leo
Keyword(s):  
Electrical Properties ◽  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Carrier Transport ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Blocking Layer ◽  
Electron Blocking Layer ◽  
Light Emitting ◽  
Organic Light

ABSTRACTThe effect of the electron blocking layer on the performance of white organic light-emitting diodes is studied. A variation of the material influences not only the carrier transport, but also the light distribution from the different emitters. Highest external quantum efficiency is reached for the material with the worst electrical properties, while highest luminous efficacy is obtained for the material with the best transport characteristics.

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