Emission Pattern Control of GaN-Based Light-Emitting Diodes with ZnO Nanostructures

We report a controllable way of changing the emission patterns of GaN-based blue light-emitting diodes (LEDs) using ZnO nanorods (NRs) grown hydrothermally. The shape of the ZnO NRs was controlled using seed layers for flower, askance, and vertical structures. The electrical properties of the LEDs with the ZnO NRs did not degrade, while the integrated electroluminescence intensity increased compared with that of the bare LEDs. The emission patterns of the LEDs were broadened as the inclination angle of the ZnO NRs increased. These are attributed to the ZnO NRs acting a role in scattering and guiding the light wave efficiently. (C) 2011 The Japan Society of Applied Physics