Title :
High light extraction efficiency light-emitting diodes grown on bulk GaN and sapphire substrates using vertical transparent package
Author :
Pan, Chih-Chien ; Nakamura, Shuji ; Den Baars, Steve P.
Author_Institution :
Mater. Dept., Univ. of California, Santa Barbara, CA, USA
Abstract :
High light extraction efficiency (LEE) of 75.86% and 77% for light-emitting diodes (LEDs) grown on free-standing GaN and patterned sapphire substrates, respectively, are demonstrated using novel vertical transparent LED (VT-LED) package. Compared to conventional silver header package with consistent external quantum efficiency (EQE) and LEE, enhancement of ~14% and ~12% for GaN and sapphire chips, respectively, are also demonstrated up to 100 A/cm2 under DC operations without any current crowding issues. Also, using high refractive index materials (n~2.1) between LED and ZnO stand, LEE of 81% and 82% for blue and green GaN chips can be achieved.
Keywords :
gallium compounds; light emitting diodes; refractive index; sapphire; substrates; transparency; Al2O3; GaN; GaN chip enhancement; VT-LED package; ZnO stand; blue GaN chips; bulk GaN substrates; external quantum efficiency; green GaN chips; light emitting diodes; light extraction efficiency; refractive index materials; sapphire chip enhancement; sapphire substrates; silver header package; vertical transparent package; Gallium nitride; Light emitting diodes; Refractive index; Silver; Substrates; Zinc oxide;
Conference_Titel :
Lasers and Electro-Optics (CLEO), 2012 Conference on
Conference_Location :
San Jose, CA
Print_ISBN :
978-1-4673-1839-6
