Enhancing the Light-Extraction Efficiency of an AlGaN Nanowire Ultraviolet Light-Emitting Diode by Using Nitride/Air Distributed Bragg Reflector Nanogratings

The performance and efficiency of AlGaN ultraviolet light-emitting diodes have been limited by the extremely low light-extraction efficiency (LEE) due to the intrinsic material properties of AlGaN. Here, to enhance the LEE of the device, we demonstrate an AlGaN nanowire light-emitting diode (NW-LED)...

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Bibliographic Details
Published in:IEEE photonics journal 2017-10, Vol.9 (5), p.1-8
Main Authors: Alias, Mohd Sharizal, Janjua, Bilal, Zhao, Chao, Priante, Davide, Alhamoud, Abdullah A., Tangi, Malleswararao, Alanazi, Lafi M., Alatawi, Abdullah A., Albadri, Abdulrahman M., Alyamani, Ahmed Y., Ng, Tien Khee, Ooi, Boon S.
Format: Article
Language:English
Subjects:
AlGaN
Aluminum gallium nitride
DBR gratings
Distributed Bragg reflectors
Etching
LED
Light emitting diodes
Nanoscale devices
nanowires
Reflectivity
Wide band gap semiconductors
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Summary:The performance and efficiency of AlGaN ultraviolet light-emitting diodes have been limited by the extremely low light-extraction efficiency (LEE) due to the intrinsic material properties of AlGaN. Here, to enhance the LEE of the device, we demonstrate an AlGaN nanowire light-emitting diode (NW-LED) integrated with nitride/air distributed Bragg reflector (DBR) nanogratings. Compared to a control device (only mesa), the AlGaN NW-LED with the nitride/air DBR nanogratings exhibits enhancement in the light output power and external quantum efficiency (EQE) by a factor of ∼1.67. The higher light output power and EQE are attributed mainly to the multiple reflectances laterally for the transverse magnetic (TM)-polarized light and scattering introduced by the nanogratings. To further understand the LEE enhancement, the electrical field distribution, extraction ratio, and polar pattern of the AlGaN NW-LED with and without the nitride/air DBR nanogratings were analyzed using the finite-difference time-domain method. It was observed that the TM-field emission was confined and scattered upward, whereas the polar pattern was intensified for the AlGaN NW-LED with the nanogratings. Our approach to enhance the LEE via the nitride/air DBR nanogratings can provide a promising route for increasing the efficiency of AlGaN-based LEDs, also, to functioning as facet mirror for AlGaN-based laser diodes.
ISSN:1943-0655
1943-0655
1943-0647
DOI:10.1109/JPHOT.2017.2749198