A charge inverter for III-nitride light-emitting diodes

Date
2016
Advisor
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Source Title
Applied Physics Letters
Print ISSN
0003-6951
Electronic ISSN
Publisher
American Institute of Physics Inc.
Volume
108
Issue
13
Pages
133502-1 - 133502-5
Language
English
Type
Article
Journal Title
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Abstract

In this work, we propose a charge inverter that substantially increases the hole injection efficiency for InGaN/GaN light-emitting diodes (LEDs). The charge inverter consists of a metal/electrode, an insulator, and a semiconductor, making an Electrode-Insulator-Semiconductor (EIS) structure, which is formed by depositing an extremely thin SiO2 insulator layer on the p+-GaN surface of a LED structure before growing the p-electrode. When the LED is forward-biased, a weak inversion layer can be obtained at the interface between the p+-GaN and SiO2 insulator. The weak inversion region can shorten the carrier tunnel distance. Meanwhile, the smaller dielectric constant of the thin SiO2 layer increases the local electric field within the tunnel region, and this is effective in promoting the hole transport from the p-electrode into the p+-GaN layer. Due to the improved hole injection, the external quantum efficiency is increased by 20% at 20 mA for the 350 × 350 μm2 LED chip. Thus, the proposed EIS holds great promise for high efficiency LEDs.

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Keywords
Charge injection, Efficiency, Electric fields, Electric inverters, Electrodes, Electron injection, Gallium nitride, Semiconductor diodes, Wide band gap semiconductors, External quantum efficiency, High-efficiency, Hole transports, Improved hole injection, Ingan/gan lightemitting diodes (LEDs), Insulator layer, Local electric field, Weak inversion region, Light emitting diodes
Citation
Published Version (Please cite this version)