title: Improved light output from InGaN LEDs by laser-induced dumbbell-like air-voids.
abstract: 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.
authors: Yiyun
authors: Y
authors: Zhang
authors: Haizhong
authors: H
authors: Xie
authors: Haiyang
authors: H
authors: Zheng
authors: Peng
authors: P
authors: Dong
authors: Hua
authors: H
authors: Yang
authors: Xiaoyan
authors: X
authors: Yi
authors: Guohong
authors: G
authors: Wang