Highly efficient and bright LEDs overgrown on GaN nanopillar substrates

Ching Hsueh Chiu*, Po Min Tu, Chien-Chung Lin, Da Wei Lin, Zhen Yu Li, Kai Lin Chuang, Jet Rung Chang, Tien-chang Lu, Hsiao-Wen Zan, Chiang Yao Chen, Hao-Chung Kuo, Shing Chung Wang, Chun Yen Chang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


We presented a study of high-performance GaN-based light emitting diodes (LEDs) using a GaN nanopillars (NPs) structure grown on sapphire substrate by integrating RF-plasma molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). Nanoscale air voids were clearly observed at the interface between GaN NPs and the overgrown GaN layer by cross-sectional scanning electron microscopy. It can increase the light-extraction efficiency due to additional light scattering. The transmission electron microscopy images suggest the air voids between GaN NPs introduced during nanoscale epitaxial lateral overgrowth of GaN can suppress the threading dislocation density. Moreover, Raman spectrum demonstrated that the strain of the GaN layer grown on GaN NPs was effectively eliminated, resulting in the reduction of quantum-confined Stark effect in InGaN/GaN quantum wells. Consequently, the LEDs fabricated on the GaN NPs template exhibit smaller electroluminescent peak wavelength blue shift and great enhancement of the light output (70 at 20 mA) compared with the conventional LEDs.

Original languageEnglish
Article number5604636
Pages (from-to)971-978
Number of pages8
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number4
StatePublished - Jul 2011


  • Light emitting diodes (LEDs)
  • metal-organic chemical vapor deposition (MOCVD)
  • molecular beam epitaxy (MBE)
  • quantum-confined Stark effect (QCSE)


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