Fabrication and characteristics of thin-film InGaN-GaN light-emitting diodes with TiO2 /SiO2 omnidirectional reflectors

C. H. Chiu*, Hao-Chung Kuo, C. E. Lee, C. H. Lin, P. C. Cheng, H. W. Huang, Tien-chang Lu, S. C. Wang, K. M. Leung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

In this paper, a novel GaN-based thin-film vertical injection light-emitting diode (LED) structure with a TiO 2 and SiO 2 omnidirectional reflector (ODR) and an n-GaN rough surface is designed and fabricated. The designed ODR, consisting of alternating TiO 2 and SiO 2 , layers possesses a complete photonic band gap within the blue region of interest. The arrays of the conducting channels are integrated into the TiO 2 /SiO 2 ODR structure for vertically spreading the current. Assisted by the laser lift-off and photo-enhanced chemically etched surface roughening process, the light output power and the external quantum efficiency of our thin-film LED with a TiO 2 /SiO 2 ODR (at a driving current of 350 mA and with chip size of 1 mm × 1 mm) reached 330 mW and 26.7%, increased by 18% and 16%, respectively, compared with the results from the thin-film LED with an Al mirror. By examining the radiation patterns of the LEDs, the optical output power mainly increased within the 120 deg cone due to the higher reflectance of the TiO 2 /SiO 2 ODR within the blue regime.

Original languageEnglish
Article number029
Pages (from-to)831-835
Number of pages5
JournalSemiconductor Science and Technology
Volume22
Issue number7
DOIs
StatePublished - 1 Jul 2007

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