Title :
Enhancement of Light Extraction for InGaN LEDs by Means of Beveled Sapphire and Cup-Shaped Copper Sheeting
Author :
Horng, Ray-Hua ; Hu, Hung-Lieh ; Ou, Sin-Liang ; Lin, Re-Ching ; Hsu, Chen-Peng
Author_Institution :
Grad. Inst. of Precision Eng., Nat. Chung Hsing Univ., Taichung, Taiwan
Abstract :
In this letter, InGaN light-emitting diode (LED) structures fabricated with beveled sapphire substrates and embedded in cup-shaped copper sheets are presented. Using Trace-Pro simulation, the shaped sapphire with an optimum beveled angle of 75° was determined to enhance the light extraction of LEDs. The thermal dissipation for high power LEDs can be improved by embedding them in cup-shaped copper sheets. At an injection current of 350 mA, the output powers of LED with conventional structure and LEDs with original and beveled sapphires, both embedded in cup-shaped copper sheets, are 325.4, 372.6, and 395.6 mW, respectively, while the power efficiencies are 27.6%, 31.5%, and 33.3%, respectively. It indicates that the light extraction and output power of LED devices can be enhanced with the aid of beveled sapphires and cup-shaped copper sheets.
Keywords :
III-V semiconductors; copper; gallium compounds; indium compounds; light emitting diodes; sapphire; wide band gap semiconductors; InGaN; Trace-Pro simulation; beveled sapphire; cup shaped copper sheeting; current 350 mA; injection current; light emiiting diodes; light extraction; power 325.4 mW; power 372.6 mW; power 395.6 mW; power efficiency; thermal dissipation; Copper; Gallium nitride; Heating; Light emitting diodes; Performance evaluation; Power generation; Substrates; Beveled sapphire; InGaN; cup-shaped copper sheet; light extraction; light-emitting diode (LED);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2012.2203800
