Optical and Thermal Analyses of Thin-Film Hexagonal Micro-Mesh Light-Emitting Diodes

Author

Kwai Hei Li ; Yuk Fai Cheung ; Qian Zhang ; Hoi Wai Choi

Author_Institution

Dept. of Electr. & Electron. Eng., Univ. of Hong Kong, Hong Kong, China

Volume

25

Issue

4

fYear

2013

fDate

Feb.15, 2013

Firstpage

374

Lastpage

377

Abstract

Vertical thin-film light-emitting diodes (LEDs) with integrated micro-mesh arrays are reported. By removing the sapphire substrate through laser lift-off, vertical current conduction becomes possible, improving current spreading capability and thus electrical properties. Compared with the as-grown device, the thin-film micro-mesh LEDs emits 61% more optical power, attributed to enhanced light extraction through the micro-mesh, evidence of which is provided by confocal imaging. At 100 mA, the enhancement factor rises to >;100% attributed to low junction temperatures due to efficient heat conduction as verified by infrared thermometric imaging.

Keywords

electrical conductivity; infrared imaging; integrated optoelectronics; light emitting diodes; micro-optics; optical arrays; thermal conductivity; thin film devices; Al₂O₃; confocal imaging; current 100 mA; current spreading capability; electrical properties; heat conduction; infrared thermometric imaging; integrated micromesh arrays; junction temperature; laser lift-off; light extraction; optical analysis; optical power; sapphire substrate; thermal analysis; thin-film hexagonal micromesh light-emitting diodes; thin-film micromesh LED; vertical current conduction; vertical thin-film light-emitting diodes; Gallium nitride; Heating; Indium tin oxide; Junctions; Light emitting diodes; Substrates; Surface treatment; Light-emitting diodes (LEDs); light extraction; thin film;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2013.2238621

Filename

6409387