Polarization-Dependent Sidewall Light Diffraction of LEDs Surrounded by Nanorod Arrays

The polarization behavior of the light-emitting diodes (LEDs) with nanorods surrounding the p-mesa is investigated. The nanorods were fabricated using a natural nanosphere lithography and are intended to diffract laterally propagated light. In the horizontal direction, s-polarized light is dominated since the injected carriers choose to fill up the lowest energy state in a direction parallel to the quantum-well layers. The p/s-polarized ratio starts to increase with the increase of radiated angles and eventually saturates. Since the Bragg diffraction of laterally propagated p-polarized mode by nanorods is more efficient than the s-polarized light, the p/s-ratio of the device with nanorods is higher than that without rods. The p/s-ratio of the LED with nanorods is 1.96 at 90^deg, and is 1.52 when the integrating intensity between 0^deg and 90^deg is considered.