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

• Published in: IEEE photonics technology letters Vol. 18; no. 10; pp. 1152 - 1154
• Main Authors: 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.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2006; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Chemicals; Crystallography; Dislocation density; Emittance; Etching; Fabrication; Gallium nitride; GaN; Injection current; Light emitting diodes; Light scattering; light-emitting diode (LED); Power generation; Sapphire; sapphire chemical wet etching; Shape; Substrates; Wavelengths; Wet etching
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2006.874737

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 57/spl deg/ 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.