Study of GaN-based light-emitting diodes grown on chemical wet-etching-patterned sapphire substrate with V-shaped pits roughening surfaces

Ya-Ju Lee, Hao Chung Kuo, Tien Chang Lu, Shing Chung Wang, Kar Wai Ng, Kei May Lau, Zu Po Yang, Allan Shih Ping Chang, Shawn Yu Lin

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We investigate the mechanism responding for performance enhancement of gallium nitride (GaN)-based light-emitting diode (LED) grown on chemical wet-etching-patterned sapphire substrate (CWE-PSS) with V-Shaped pit features on the top surface. According to temperature-dependent photoluminescence (PL) measurement and the measured external quantum efficiency, the structure can simultaneously enhance both internal quantum efficiency and light extraction efficiency. Comparing to devices grown on planar sapphire substrate, the threading dislocation defects of LED grown on CWE-PSS are reduced from 1.28 × 109/ cm2 to 3.62 × 108/cm, leading to a 12.5% enhancement in internal quantum efficiency. In terms of the theoretical computing of radiation patterns, the V-Shaped pits roughening surface can be thought of as a strong diffuser with paraboloidal autocorrelation function, increasing the escape probability of trapped photons and achieving a 20% enhancement in light extraction efficiency. Moreover, according to the measurement of optical diffraction power, CWE-PSS demonstrated superior guided light extraction efficiency than that of planar sapphire substrate, thus an extra 7.8% enhancement in light extraction efficiency was obtained. Therefore, comparing to the conventional LED, an overall 45% enhancement in integrated output power was achieved.

Original languageEnglish
Pages (from-to)1455-1463
Number of pages9
JournalJournal of Lightwave Technology
Volume26
Issue number11
DOIs
Publication statusPublished - 2008 Jun 1

Fingerprint

Gallium nitride
Wet etching
gallium nitrides
Sapphire
Light emitting diodes
sapphire
light emitting diodes
etching
Quantum efficiency
augmentation
Substrates
quantum efficiency
diffusers
Autocorrelation
autocorrelation
escape
Photoluminescence
Photons
Diffraction
photoluminescence

Keywords

  • Epitaxial growth
  • Light-emitting diodes (LEDs)
  • Optical device fabrication

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Study of GaN-based light-emitting diodes grown on chemical wet-etching-patterned sapphire substrate with V-shaped pits roughening surfaces. / Lee, Ya-Ju; Kuo, Hao Chung; Lu, Tien Chang; Wang, Shing Chung; Ng, Kar Wai; Lau, Kei May; Yang, Zu Po; Chang, Allan Shih Ping; Lin, Shawn Yu.

In: Journal of Lightwave Technology, Vol. 26, No. 11, 01.06.2008, p. 1455-1463.

Research output: Contribution to journalArticle

Lee, Ya-Ju ; Kuo, Hao Chung ; Lu, Tien Chang ; Wang, Shing Chung ; Ng, Kar Wai ; Lau, Kei May ; Yang, Zu Po ; Chang, Allan Shih Ping ; Lin, Shawn Yu. / Study of GaN-based light-emitting diodes grown on chemical wet-etching-patterned sapphire substrate with V-shaped pits roughening surfaces. In: Journal of Lightwave Technology. 2008 ; Vol. 26, No. 11. pp. 1455-1463.
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