Light Output Power Enhancement of GaN-based Vertical Light Emitting Diodes via Fabricating Surface Nanorod Arrays

Abstract

In this research, we demonstrated two approaches to fabricate nanorod arrays on the surface of GaN-based vertical light emitting diodes (VLEDs). The first approach was via synthesizing single-crystal ZnO nanorod arrays in aqueous solution at room temperature. The light output intensity and wall-plug efficiency of the GaN-based VLEDs with the ZnO nanorod arrays shows 38.9 and 41.2% increases, respectively, at 200 mA current injections compared to that of a VLED without ZnO nanorod arrays. The second approach was formed by spinning nano silica spheres and inductively coupled plasma-reactive ion etching. The light output power of the VLEDs with the dry etched nanorod arrays showed about 40% enhancement than that without the nanorod arrays. The large enhancement of VLED with both ZnO or GaN nanorod arrays was mainly due to the total internal reflection destruction, and the gradually changed refractive index from the nanorod arrays layer.