The Impact of Resonance on the Light Extraction Efficiency of Single Nanowire Ultraviolet Light Emitting Diodes

Fabricating the nanowire ultraviolet light emitting diodes (UV LEDs) has been a promising candidate to dramatically enhance the external quantum efficiency (EQE) of UV LEDs. For a great luminescent performance, it is necessary to understand the propagating features of light inside the nanowire. The relationship between the resonance inside the nanowire, the light extraction efficiency (LEE) and the far-field distribution of nanowire UV LEDs, as well as the geometrical parameters of the nanowire and the impact of surrounding index has been discussed in this paper. It is shown that the resonance plays an important role to enhance the LEE at various parameters. The study on the far-field distribution indicates that the variation of far-field patterns at different conditions can be conveniently explained by the geometrical optics theory. This deep understanding provides benefits to design the nanowire UV LEDs.