Title :
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
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;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2012.2210542
