Title :
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
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.;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2014.2320957
