Light extraction enhancement analysis of GaN-based LED with surface spherical crown array

For promoting the light extraction efficiency (LEE) of GaN-LED with nano-spherical hexagonal arrays, finite-difference time-domain (FDTD) method was used for optimizing the structure parameters such as spherical radius and height. The LEE of GaN spherical crown hexagonal array with 473nm radius and 250nm height over the LED surface exhibited 5.7 times enhancement than that of the planar LED, better than the LEE of whole-sphere array and pure-hemisphere array both.