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AlGaN-based deep UV LEDs grown on sputtered and high temperature annealed AlN/sapphire

Authors :
Michael Kneissl
Dominik Jaeger
Frank Mehnke
Markus Weyers
Christoph Reich
Norman Susilo
Ute Zeimer
Bettina Neuschulz
Sylvia Hagedorn
Luca Sulmoni
Martin Guttmann
Hideto Miyake
Tim Wernicke
Christian Kuhn
Source :
Applied Physics Letters. 112:041110
Publication Year :
2018
Publisher :
AIP Publishing, 2018.

Abstract

The performance characteristics of AlGaN-based deep ultraviolet light emitting diodes (UV-LEDs) grown by metalorganic vapor phase epitaxy on sputtered and high temperature annealed AlN/sapphire templates are investigated and compared with LEDs grown on epitaxially laterally overgrown (ELO) AlN/sapphire. The structural and electro-optical properties of the devices on 350 nm sputtered and high temperature annealed AlN/sapphire show similar defect densities and output power levels as LEDs grown on low defect density ELO AlN/sapphire templates. After high temperature annealing of the 350 nm sputtered AlN, the full widths at half maximum of the (0002) and (101¯2) reflections of the high resolution x-ray diffraction rocking curves decrease by one order of magnitude to 65 arc sec and 240 arc sec, respectively. The curvature of the sputtered and HTA AlN/sapphire templates after regrowth with 400 nm MOVPE AlN is with −80 km−1 much lower than the curvature of the ELO AlN/sapphire template of −160 km−1. The on-wafer measured output powers of 268 nm LEDs grown on 350 nm sputtered and high temperature annealed AlN/sapphire templates and ELO AlN/sapphire templates were 0.70 mW and 0.72 mW at 20 mA, respectively (corresponding to an external quantum efficiency of 0.75% and 0.78%). These results show that sputtered and high temperature annealed AlN/sapphire provide a viable approach for the fabrication of efficient UVC-LEDs with reduced complexity and thus reduced costs.

Details

ISSN :
10773118 and 00036951
Volume :
112
Database :
OpenAIRE
Journal :
Applied Physics Letters
Accession number :
edsair.doi...........91168c47fb3bea1f4b46bd58ff614bdf
Full Text :
https://doi.org/10.1063/1.5010265