Open AccessImproved light output from InGaN LEDs by laser-induced dumbbell-like air-voids
Author(s) -
Yiyun Zhang,
Hongtao Xie,
Hui Zheng,
Peng Dong,
Hua Yang,
Xiaoyan Yi,
Guohong Wang
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.032582
Subject(s) - materials science , light emitting diode , optoelectronics , optics , laser , sapphire , diode , electric field , physics , quantum mechanics
We report inducing an array of dumbbell-like air-voids inside the sapphire substrate in InGaN-based light-emitting diodes (LEDs) to improve the light extraction from LED device by a picosecond (Ps) pulse laser. At an injection current of 100 mA, the light output power (LOP) of packaged LEDs with laser-induced air-voids can be improved by 24.7% compared with conventional LEDs. Far-field radiation pattern has verified that this great improvement in LOP is due to the light scattering occurred at the interface of sapphire/air-voids. Current-Voltage curves show that the laser processing of air-voids will not degrade the LED electrical properties. Furthermore, leakage current at a level of ~5 nA at -10V has demonstrated an enhancement in the LED electrical performance with laser-induced air-voids. Second focusing mechanism, which is originated in the local heating effect around the laser focus, has been proposed to explain the formation of dumbbell-like air-voids.