title: Improved light extraction efficiency of InGaN-based multi-quantum well light emitting diodes by using a single die growth.
abstract: We have demonstrated that the light extraction efficiency of the InGaN based multi-quantum well light-emitting diodes (LEDs) can be improved by using a single die growth (SDG) method. The SDG was performed by patterning the n-GaN and sapphire substrate with a size of single chip (600 x 250 microm2) by using a laser scriber, followed by the regrowth of the n-GaN and LED structures on the laser patterned n-GaN. We fabricated lateral LED chips having the SDG structures (SDG-LEDs), in which the thickness of the regrown n-GaN was varied from 2 to 6 microm. For comparison, we also fabricated conventional LED chips without the SDG structures. The SDG-LEDs showed lower operating voltage when compared to the conventional LEDs. In addition, the output power of the SDG-LEDs was significantly higher than that of the conventional LEDs. From optical ray tracing simulations, the increase in the thickness and sidewall angle of the regrown n-GaN and LED structures may enhance photon escapes from the tilted facets of the regrown n-GaN, followed by the increase in light output power and extraction efficiency of the SDG-LEDs.
authors.affiliation: Department of Printed Electronics Engineering, Sunchon National University, Jeonnam 540-742, Korea.
authors.forename: Min Joo
authors.initials: MJ
authors.lastname: Park
authors.forename: K W
authors.initials: KW
authors.lastname: Kwon
authors.forename: Y H
authors.initials: YH
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Park
authors.forename: Joon Seop
authors.initials: JS
authors.lastname: Kwak