GaN-based light-emitting diodes (LEDs) were grown on a patterned sapphire substrate (PSS) containing hemispheres on the growth surface. Free-standing LED structures were obtained by removing the PSS using laser lift-off technique. The N-face GaN surface with micron-sized concave hemisphere structures, which had been located between the sapphire and the GaN film, was then exposed and photo-electrochemically etched using a 2M KOH solution to create nano-sized pyramids. Aluminum was deposited on the roughened N-face GaN as a reflective layer. The roughened aluminum reflectors, consisting of micron-sized hemisphere structures and nano-sized pyramids, enhanced the light extraction efficiency through multiple scattering events of photons and randomized the directions of the photons. The subsequent enhancement in electroluminescence was 13 compared with an untextured control LED.
|Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
|Published - 2012 Sept
Bibliographical noteFunding Information:
The research at Korea University was supported by LG Innotek-Korea University Nano-Photonics Program and by a Korea University Grant. The research at UNIST was supported by Future-based Technology Development Program (Nano Fields) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (Grant No. 2010-0029300). The work at UF was partially supported by US Dept. Commerce (NIST) Contract No. 70NANB11H009.
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films