Ambipolar charge transport and electroluminescence properties of ZnO nanorods

Hexagonal ZnO nanorod arrays have been prepared by a simple low-temperature ZnO-nanocrystal-assisted hydrothermal method. The photoluminescence spectrum of the ZnO nanorods features a weak band-edge emission at λmax ∼3.3 eV and a strong broad yellow emission at λmax ∼2.17 eV. Unlike the conventional reported n -type semiconducting property, our ZnO nanorods exhibit ambipolar charge transporting behavior. Using bottom contact field-effect transistor structure, the ZnO nanorods exhibit electron and hole mobilities up to 3.2 and 2.1 cm2 V^-1 s^-1, respectively. Electroluminescence in the visible region from the nanorod-based device has also been demonstrated.