• ZnO nanowires and nanorods are also potentially good candidates for nanometre scale photonic device applications, ultraviolet photo-detectors and light emitting devices. Both p-type ZnO nanowires and n-type ZnO nanowires can be produced as positively and negatively charged semiconducting materials, this forms good foundation to make light emitting diodes (LED), in which, as an electron meets a hole, it falls into a lower energy level and releases energy in the form of a photon of light.