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Proceedings Paper

Removal and passivation of surface defects in perforated GaN-based light-emitting diodes
Author(s): Y. Yang; X. A. Cao
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Paper Abstract

Perforated GaN-based light-emitting diodes (LEDs) with an array of plasma-etched microholes penetrating through the active region were fabricated using lithography and plasma etching. Plasma damage on the microhole sidewalls led to an increase in junction leakage by up to seven orders of magnitude and a reduced light emission in the low injection regime. It was found that KOH can etch off the plasma-damaged materials, leading to a complete suppression of surface leakage currents. It however attacked metal contacts and increased the forward turn-on voltage. Thermal annealing removed damage in the near-surface bulk region, whereas (NH4)2S treatment only passivated the defect states at the immediate surfaces. Both methods produced a partial restoration of the forward-bias characteristics. It has been demonstrated that annealing at 700 °C used in conjunction with prolonged sulfide passivation can remove or passivate all plasma-induced defects and result in a complete suppression of surface leakage in the perforated LEDs. This work is an important step toward developing high-efficiency photonic crystal-integrated LEDs, in which light can only be coupled to radiation modes but the undesirable guided light emission is inhibited.

Paper Details

Date Published: 12 October 2009
PDF: 6 pages
Proc. SPIE 7518, Photonics and Optoelectronics Meetings (POEM) 2009: Solar Cells, Solid State Lighting, and Information Display Technologies, 75180V (12 October 2009); doi: 10.1117/12.841361
Show Author Affiliations
Y. Yang, West Virginia Univ. (United States)
X. A. Cao, West Virginia Univ. (United States)

Published in SPIE Proceedings Vol. 7518:
Photonics and Optoelectronics Meetings (POEM) 2009: Solar Cells, Solid State Lighting, and Information Display Technologies
Michael Grätzel; Hiroshi Amano; Chin Hsin Chen; Changqing Chen; Peng Wang, Editor(s)

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