A hole modulator for InGaN/GaN light-emitting diodes
Author
Zhang, Z-H.
Kyaw, Z.
Liu W.
Ji Y.
Wang, L.
Tan S.T.
Sun, X. W.
Demir, Hilmi Volkan
Date
2015Source Title
Applied Physics Letters
Print ISSN
0003-6951
Electronic ISSN
1077-3118
Publisher
American Institute of Physics
Volume
106
Issue
6
Pages
063501-1 - 063501-5
Language
English
Type
ArticleItem Usage Stats
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Abstract
The low p-type doping efficiency of the p-GaN layer has severely limited the performance of InGaN/GaN light-emitting diodes (LEDs) due to the ineffective hole injection into the InGaN/GaN multiple quantum well (MQW) active region. The essence of improving the hole injection efficiency is to increase the hole concentration in the p-GaN layer. Therefore, in this work, we have proposed a hole modulator and studied it both theoretically and experimentally. In the hole modulator, the holes in a remote p-type doped layer are depleted by the built-in electric field and stored in the p-GaN layer. By this means, the overall hole concentration in the p-GaN layer can be enhanced. Furthermore, the hole modulator is adopted in the InGaN/GaN LEDs, which reduces the effective valance band barrier height for the p-type electron blocking layer from ∼332meV to ∼294 meV at 80 A/cm2 and demonstrates an improved optical performance, thanks to the increased hole concentration in the p-GaN layer and thus the improved hole injection into the MQWs.
Keywords
Charge injectionElectric fields
Electron injection
Gallium nitride
Heterojunction bipolar transistors
Hole concentration
Light modulators
Modulators
Semiconducting indium compounds
Semiconductor quantum wells
Active regions
Built - in electric fields
Electron blocking layer
Improved hole injection
Ingan/gan leds
Ingan/gan lightemitting diodes (LEDs)
Optical performance
Valance band barriers
Light emitting diodes