Micro-Chip Shaping for Luminance Enhancement of GaN Micro-Light-Emitting Diodes Array

Author

Ying-Chien Chu ; Ming-Hsien Wu ; Chi-jui Chung ; Yen-Hsiang Fang ; Yan-Kuin Su

Author_Institution

Dept. of Electr. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan

Volume

35

Issue

7

fYear

2014

fDate

Jul-14

Firstpage

771

Lastpage

773

Abstract

Significant luminance enhancement of GaN microlight-emitting diode (μLED) array was achieved by micro-chip shaping (μCS) technique. The μCSs with a shaped angle of 70° and an etched depth of 1 μm on the sidewall of μLEDs with 10-, 16-, and 50-μm pixel sizes, respectively, refract light rays through sidewalls into the light extraction cone and consequently improve the luminance. The μCSs enhance more luminance on μLED with small sizes. The maximum efficiency improvement on the μCS μLED array is over 45% compared with the vertical sidewall μLED array. Furthermore, the efficiency improvement exceeds 48% measured within ±15° extraction cone. The raytracing simulation also confirms the μCS effect.

Keywords

III-V semiconductors; brightness; etching; gallium compounds; light emitting diodes; ray tracing; wide band gap semiconductors; μCS μLED array; μCS effect; μCS technique; GaN; light extraction cone; light rays; luminance enhancement; micro-light-emitting diode array; microchip shaping; raytracing simulation; vertical sidewall μLED array; Arrays; Current density; Gallium nitride; Light emitting diodes; Photonic crystals; Ray tracing; Substrates; Micro-chip shaping ( (mu ) CS); Micro-chip shaping (μCS); extraction efficiency; micro-light-emitting diode ( (mu ) LED) array; micro-light-emitting diode (μLED) array; ray-tracing; ray-tracing.;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2014.2320957

Filename

6813587