Abstract
The enhancement of light extraction efficiency of InGaN quantum well (QW) light emitting diodes (LEDs) was achieved by employing the refractive index matched TiO2 microsphere arrays. The optimization studies of the dipping method and rapid convective deposition (RCD) method were carried out for the deposition of TiO2 microsphere arrays onto LEDs. The 2-dimensional relatively close-packed and close-packed TiO2 microsphere arrays were deposited by the using optimized conditions of the dipping method and RCD method, respectively. The light extraction efficiencies of LEDs under electrical injection were enhanced by 1.83 times by utilizing 520-nm diameter TiO2 microspheres. This enhancement is primarily attributed to increase in the effective photon escape cone due to the matched index and spherical shape of TiO2 microstructures arrays.