Modulated Epitaxial Lateral Overgrowth of AlN for Efficient UV LEDs

A reduction of the threading dislocation density in AlN layers on a sapphire from 10 10 cm -2 to 10 9 cm -2 was achieved by applying epitaxial lateral overgrowth (ELO) of patterned AlN and sapphire templates. By varying the growth temperature, it is possible to influence the lateral growth rate and...

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Veröffentlicht in:IEEE photonics technology letters 2012-09, Vol.24 (18), p.1603-1605
Hauptverfasser: Kueller, V., Knauer, A., Reich, C., Mogilatenko, A., Weyers, M., Stellmach, J., Wernicke, T., Kneissl, M., Zhihong Yang, Chua, C. L., Johnson, N. M.
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Sprache:eng
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Zusammenfassung:A reduction of the threading dislocation density in AlN layers on a sapphire from 10 10 cm -2 to 10 9 cm -2 was achieved by applying epitaxial lateral overgrowth (ELO) of patterned AlN and sapphire templates. By varying the growth temperature, it is possible to influence the lateral growth rate and modulate the thickness before coalescence. With a two-step growth at two different temperatures, up to 11-μm thick crackfree layers were achieved. Using these ELO AlN templates, the light emitting diode (LED) output power was >;1 mW dc at 295 nm and ~ 4mW at 324 nm which is a significant increase compared to planar templates. The usefulness of modulated ELO AlN templates for ultraviolet LEDs has thus been validated.
ISSN:1041-1135
1941-0174
DOI:10.1109/LPT.2012.2210542