"Improved performance of electron blocking layer free algan deep ultrav" by Barsha Jain, Ravi Teja Velpula et al.
 

Improved performance of electron blocking layer free algan deep ultraviolet light-emitting diodes using graded staircase barriers

Document Type

Article

Publication Date

3-1-2021

Abstract

To prevent electron leakage in deep ultraviolet (UV) AlGaN light-emitting diodes (LEDs), Al-rich p-type Alx Ga(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.

Identifier

85103479351 (Scopus)

Publication Title

Micromachines

External Full Text Location

https://doi.org/10.3390/mi12030334

e-ISSN

2072666X

Issue

3

Volume

12

Grant

ECCS-1944312

Fund Ref

National Science Foundation

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