title: Micro/nano structures induced by femtosecond laser to enhance light extraction of GaN-based LEDs.
abstract: Surface texturing has been widely adopted to enhance the light extraction efficiency of light-emitting diodes (LEDs), and chemical etching is a technique commonly used to produce surface texturing. This study employed femtosecond lasers to apply ITO films directly onto the surface of LEDs to generate periodic micro/nanostructures and roughen the surface without contact or chemical substances. As a result, photons emitted in the active region escape into the free space, due to the scattering effect produced by texturing. This study discovered that light-emitting efficiency increases with surface roughness, and achieved an improvement of 18%. Caution regarding laser fluence was required during laser processing to avoid damaging the LED beneath the ITO film, which could detract from the electrical characteristics.
authors: Department of Mechatronic Technology,National Taiwan Normal University, Taipei 10644, Taiwan.
authors: Tien-Li
authors: TL
authors: Chang
authors: Zhao-Chi
authors: ZC
authors: Chen
authors: Yeeu-Chang
authors: YC
authors: Lee