High efficient vertical LED with pattern surface texture

A quantitative investigation of light extraction efficiency for hemispherical and pyramidal pattern surface textured GaN based vertical light emitting diode (VLED) was reported by various distance and size ratios. There is a significant increase in light extraction efficiency because of increase number of random scattering of textured surface. Hemisphere pattern surface always gives the 30% better enhancement than pyramid type pattern. We also showed the efficiency dependency on the reflectivity of GaN/metal interface. Furthermore, a linear diffraction grating with certain grating period can eliminate the distance and size ratio dependency on output power which can be considered as an integrated surface texture.