Title :
Light Output Enhancement of UV Light-Emitting Diodes With Embedded Distributed Bragg Reflector
Author :
Cheng, Bo-Siao ; Chiu, Ching-Hsueh ; Lo, Ming-Hua ; Wu, Yun-Lin ; Kuo, Hao-Chung ; Lu, Tien-Chang ; Cheng, Yuh-Jen ; Wang, Shing-Chung ; Huang, Kuo-Jui
Author_Institution :
Dept. of Photonics, Nat. Chiao Tung Univ., Hsinchu, Taiwan
fDate :
5/15/2011 12:00:00 AM
Abstract :
We demonstrate the output power enhancement of ultraviolet light-emitting diodes (UVLEDs) by epitaxial lateral over growth (ELOG) on a distributed Bragg reflector (DBR) patterned substrate. The patterned DBR mesas are used as ELOG masks to improve material quality as well as reflectors to enhance the light output coupling. Compared with the conventional UVLEDs, the surface pit density of UVLEDs at regions right above embedded patterned DBR were reduced from 2.5 × 106 to 1.6 × 106 cm-2. The improved light extraction efficiency is verified by ray tracing simulation. The luminous intensity of this novel structure is enhanced by 75% compared to that of reference UVLED structure at the wavelength 390 nm.
Keywords :
III-V semiconductors; MOCVD; chemical beam epitaxial growth; distributed Bragg reflectors; gallium compounds; light emitting diodes; semiconductor growth; GaN; UV light emitting diodes; UVLED; embedded distributed Bragg reflector; epitaxial lateral over growth; light extraction efficiency; light output coupling; light output enhancement; luminous intensity; output power enhancement; ray tracing simulation; surface pit density; wavelength 390 nm; Distributed Bragg reflectors; Epitaxial growth; Gallium nitride; Light emitting diodes; Power generation; Reflectivity; Substrates; Distributed Bragg reflector (DBR); ultraviolet light-emitting diodes (UVLEDs);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2011.2121057
