Enhancing the output power of GaN-based LEDs grown on wet-etched patterned sapphire substrates

Author

Lee, Y.J. ; Hwang, J.M. ; Hsu, T.C. ; Hsieh, M.H. ; Jou, M.J. ; Lee, B.J. ; Lu, T.C. ; Kuo, H.C. ; Wang, S.C.

Author_Institution

Dept. of Photonic, Nat. Chiao Tung Univ., Hsinchu

Volume

18

Issue

10

fYear

2006

fDate

5/1/2006 12:00:00 AM

Firstpage

1152

Lastpage

1154

Abstract

GaN-based light-emitting diodes (LEDs) with emitting wavelength of 450 nm were grown on patterned sapphire substrates (PSSs) fabricated by chemical wet etching. The crystallography-etched facet was {1-102} R-plane with a 57deg against {0001} C-axis and had superior capability for enhancing light extraction efficiency. The light output power of the PSS LED was 1.15 times higher than that of the conventional LED at an injection current of 20 mA. The output power and external quantum efficiency were estimated to be 9 mW and 16.4%, respectively. The improvement was attributed not only to geometrical shapes of {1-102} crystallography-etched facets that efficiently scatter the guided light to find escape cones, but also to dislocation density reduction by adopting the PSS growth scheme

Keywords

III-V semiconductors; MOCVD; crystallography; etching; gallium compounds; light emitting diodes; semiconductor growth; 20 mA; 450 nm; 9 mW; Al₂O₃; GaN; GaN-based LED; LED growth; crystallography-etched facet; dislocation density reduction; external quantum efficiency; guided light scattering; light extraction efficiency; light-emitting diodes; metal-organic chemical vapor deposition; patterned sapphire substrates; wet-etching; Chemicals; Crystallography; Fabrication; Gallium nitride; Light emitting diodes; Light scattering; Power generation; Shape; Substrates; Wet etching; GaN; light-emitting diode (LED); sapphire chemical wet etching;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2006.874737

Filename

1629112