Well-aligned ZnO nanorod and nanopencil arrays were synthesized in a high density on ZnO/Si substrate by a low-temperature aqueous solution technique. Detailed structural characterizations revealed that the as-synthesized nanorods and nanopencils were single crystalline, with a hexagonal phase, and with growth along the [0001] direction. The room-temperature photoluminescence spectra showed a strong ultraviolet emission at 381 nm, a weak blue band at 460 nm, and a broad green emission at 580 nm. A detailed growth mechanism has been proposed for the formation of nanorods and nanopencils based on the different crystallographic habits of wurtzite hexagonal ZnO.

Controlled, ordered arrays of ZnO nanorods having a high aspect ratio of ∼30:1 and diameter of ∼50 nm were fabricated on silicon substrates by combining electron-beam lithography and simple solution growth techniques. This top-down and bottom-up hybrid approach resulted in excellent control of periodicity, location, and density of ZnO nanorod arrays on silicon substrates. The field emission measurements from the as-grown ZnO nanorod arrays showed a low turn-on field of ∼2.85 V µm−1 and a high field-enhancement factor (β) of ∼1.68 × 103.

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In this letter we reported the behavior of zinc oxide nanorods/gallium nitride (ZnO/GaN) heterojunctions at different temperatures. The well-aligned ZnO nanorods were synthesized on GaN coated alumina (Al2O3) substrate using a solution method at lower temperatures. The as-grown p-n junction diode exhibited a low turn-on voltage of ∼0.65 V with an excellent rectifying behavior. While increasing temperature, the series resistance of the device slightly increased due to the formation of metallic bonds between metal and semiconductor. These results, therefore, emphasize that the as-grown heterostructures are quite stable even at higher temperatures.