Fabrication and optical properties of blue LEDs with silica microsphere coating

We report the enhancement of light extraction efficiency of InGaN-based blue light emitting diodes by using a surface light-scattering layer. A number of SiO2 microspheres embedded into a ZrO2 thin layer played a role of a light-scattering medium. Coating the light-scattering layer on device surface, the inter- ference fringes of electroluminescence (EL) spectra were eliminated and the EL intensity around 440–450 nm was increased by a factor of 1.3. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)