The fabrication studies of silica/polystyrene (PS) colloidal microlens arrays with various aspect ratios were performed on the III-nitride light-emitting diodes (LEDs). The use of colloidal-based microlens arrays led to significant enhancement in light extraction efficiency for III-nitride LEDs. In varying the aspect ratios of the microlens arrays, the engineering of various PS thicknesses was employed by using high-temperature treatment and redeposition process. The effects of PS thickness on the light extraction efficiency and far-field emission patterns of InGaN quantum-well (QW) LEDs were studied. The total output powers of microlens LEDs with various PS thicknesses exhibited 1.932.70 times enhancement over that of planar LEDs, and the use of optimized PS layer thickness is important in leading the enhancement of the light extraction efficiency in large angular direction.
|Original language||English (US)|
|Number of pages||11|
|Journal||IEEE Photonics Journal|
|State||Published - Jun 2011|
Bibliographical noteFunding Information:
Manuscript received April 1, 2011; accepted April 26, 2011. Date of publication May 5, 2011; date of current version May 20, 2011. The work was supported by the U.S. Department of Energy under Grant NETL, DE-PS26-08NT00290, the National Science Foundation under Award 0828426, and the Class of 1961 Professorship Fund. Corresponding authors: X.-H. Li and N. Tansu (e-mail: Li@ Lehigh.Edu; Tansu@Lehigh.Edu).
- far-field radiation
- light extraction efficiency
- light-emitting diodes (LEDs)
- microlens arrays
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering