We report ZnO nanorod-graphene hybrid architectures (ZnO-G HAs) composed of regular arrays of ZnO nanorods formed on few-layer graphene films transferred to transparent and/or flexible substrates. The ZnO-G HAs exhibited a high current flow reaching ∼1.1 mA at an applied bias of 1 V and good optical transmittance in the range of 70-80%, comparable to those of a graphene layer. In addition, cathodoluminescence images and photoluminescence spectra of the ZnO-G HAs showed distinct light emission involving optical transitions in the ZnO nanorod array. Moreover, a bending test demonstrated that the ZnO-G HAs exhibit excellent mechanical flexibility and structural stability for the bending radius down to ∼4 mm. Our results suggest that the 1D-2D HAs provide unique and multiple functions as can be applicable for next-generation electronic and optoelectronic systems.

We report a type of device that combines vertical arrays of one-dimensional (1D) pillar-superlattice (PSL) structures with 2D graphene sheets to yield a class of light emitting diode (LED) with interesting mechanical, optical, and electrical characteristics. In this application, graphene sheets coated with very thin metal layers exhibit good mechanical and electrical properties and an ability to mount, in a freely suspended configuration, on the PSL arrays as a top window electrode. Optical characterization demonstrates that graphene exhibits excellent optical transparency even after deposition of the thin metal films. Thermal annealing of the graphene/metal (Gr/M) contact to the GaAs decreases the contact resistance, to provide enhanced carrier injection. The resulting PSL-Gr/M LEDs exhibit bright light emission over large areas. The result suggests the utility of graphene-based materials as electrodes in devices with unusual, nonplanar 3D architectures.

Surface polarity and shape‐controlled ZnO nanostructures are synthesized on GaN thin films using metalorganic vapor phase epitaxy (MOVPE). By adjusting the growth parameters from Zn‐rich at low temperature to O‐rich at high temperature, morphology of ZnO nanostructures was tuned from nonpolar, smooth‐surfaced ZnO nanorod nanowall networks to O‐polar, stacked pyramid‐structured ZnO nanorods.

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