Title :
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
fDate :
5/1/2006 12:00:00 AM
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;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2006.874737
