Enhanced light-extraction from hierarchical surfaces consisting of p-GaN microdomes and SiO2 nanorods for GaN-based light-emitting diodes

Cheng Han Ho, Yu Hsuan Hsiao, Der Hsien Lien, M. S. Tsai, Don Chang, Kun Yu Lai, Ching Cherng Sun, Jr-Hau He*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


We report an efficient light-extraction scheme employing the hierarchical structure, p-GaN microdomes/SiO2 nanorods (NRs), on GaN light-emitting diodes (LEDs). Compared with the flat LED, the LEDs with hierarchical surfaces exhibits a light-output improvement of 36.8%. The considerable enhancement in light-extraction efficiency is attributed to the multiple tilted surfaces of microdomes and the graded refractive indexes provided by the SiO2 NRs, reducing total internal reflection and Fresnel reflection. The enhanced optical performances are supported by the finite-difference time-domain analysis. Advances in light extraction scheme employing hierarchical structures demonstrated here pave the way to solid-state lighting technology.

Original languageEnglish (US)
Article number161104
JournalApplied Physics Letters
Issue number16
StatePublished - Oct 14 2013

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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