It is of current interest to develop the photon management with nanostructures since the ability to suppress the reflection and light trapping over a broad range of wavelengths and incident angles plays an important role in the performance of light-emitting diodes (LEDs). Superior light-extraction characteristics of nanostructures for LEDs are discussed in this talk. These advantages are mainly attributed to the subwavelength dimensions of the nanowires, which makes the nanostructures behave like an effective homogeneous medium with continuous gradient of refraction index, significantly reducing the reflection through destructive interferences. The relation between the geometrical configurations of nanostructures and the light-harvesting characteristics is discussed. We also demonstrated their applications in solar cells and photodetectors. This research paves the way to optimize the nanostructured optoelectronic devices with efficient light management by controlling structure profile of nanostructures.