Modulated Epitaxial Lateral Overgrowth of AlN for Efficient UV LEDs

Author

Kueller, Viola ; Knauer, Arne ; Reich, Christoph ; Mogilatenko, Anna ; Weyers, Markus ; Stellmach, Joachim ; Wernicke, Tim ; Kneissl, Michael ; Yang, Zhihong ; Chua, Christopher L. ; Johnson, Noble M.

Author_Institution

FerdinandBraun-Inst., Berlin, Germany

Volume

24

Issue

18

fYear

2012

Firstpage

1603

Lastpage

1605

Abstract

A reduction of the threading dislocation density in AlN layers on a sapphire from 10¹⁰ cm^-2 to 10⁹ 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.

Keywords

III-V semiconductors; MOCVD coatings; aluminium compounds; light emitting diodes; sapphire; ultraviolet sources; vapour phase epitaxial growth; wide band gap semiconductors; AlN-Al₂O₃; UV LED; lateral growth; light emitting diode; modulated epitaxial lateral overgrowth; sapphire; threading dislocation density; wavelength 295 nm; wavelength 324 nm; Aluminum gallium nitride; Epitaxial growth; Epitaxial layers; Light emitting diodes; Power generation; Surface cracks; Epitaxial growth; epitaxial layers; light emitting diodes (LEDs); semiconductor materials;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2012.2210542

Filename

6263270