Intriguing ZnO dendritic nanostructures have been synthesized by a two-step chemical vapor deposition process. Regular nanorods grow uniformly to the presynthesized ZnO nanowires on silicon substrate, the secondary nanorods are single-crystal hexagonal ZnO, and each nanorod grows along the [0001] direction. The relationship between the secondary-grown nanorods and the primary ZnO nanowire is not epitaxial due to the high temperature-increasing rate during the rapid grown process. The size and morphology of branches can be controlled by adjusting the temperature and duration of growth. Room temperature photoluminescence (PL) and mircrowave absorption properties of the ZnO dendritic nanostructures have been investigated in detail. The value of minimum reflection loss for the composite with 50 vol % ZnO dendritic nanostructures is -42 dB at 3.6 GHz with a thickness of 5.0 mm. Hierarchical nanostructures of this type are ideal objects for the fabrication of nanoscale functional devices.

ZnO nanocombs and nanorods with different morphologies have been successfully synthesized through a simple metal vapour deposition route at 600–750 °C using pure zinc powder or zinc and graphite powders as source materials. The structures and morphologies of the products were characterized in detail by using x-ray diffraction, scanning electron microscopy, transmission electron microscopy and laser Raman spectrometer. The morphologies of the products can be easily controlled by tuning the following four factors: reaction temperature, the distance between the source and the substrates, the kinds of substrates and the kinds of precursors. Possible growth mechanisms for the formation of ZnO nanostructures with different morphologies are discussed. Photoluminescence studies show that there are sharp UV and broad defect-related green emissions for all products. Relative intensity of the UV to defect-related green emissions decreases from ZnO nanorods to nanocombs. Microwave absorption properties of these nanocombs are also investigated. The value of the minimum reflection loss is −12 dB at 11 GHz for the ZnO nanocomb composite with a thickness of 2.5 mm.

We report a controllable method for fabricating hexagonal Sn doped ZnO microdisks. The photoluminescence mechanism of the Sn doped ZnO microdisks is investigated, the defect emission is attributed to the singly charged oxygen vacancy. Under the excitation of a femtosecond pulsed laser with a wavelength of 325 nm, exciton-exciton collision process is clearly demonstrated, and amplified spontaneous emission is further realized under strong excitation. Using the perfect hexagonal symmetric structure of the Sn doped ZnO microdisks, the whispering-gallery mode lasing with high quality factor and fine mode structure is obtained from a single microdisk

We have illustrated a new approach to fabricate two forms of AlN/ZnO heterostructures―AlN/ZnO coaxial nanotubular heterostructures (CNHs) and AlN-nanotube/ZnO-nanoparticles heterostructures (AlN/ZnO NPs). X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that ZnO nanotubes and nanoparticels have grown on the inner surface of amorphous and polycrystalline AlN shell layer, respectively. A possible growth mechanism on the formation of different AlN/ZnO heterostructures is given. Compared with bare ZnO nanofibers, AlN/ZnO CNHs exhibited remarkable enhanced ultraviolet (UV) emission, while AlN/ZnO NPs showed significant visible emission. With the aid of classical optical diffraction effect theory, it can be calculated that nanoscale luminescent materials have a higher external luminescent efficiency with increasing surface/volume ratio. The influence of carrier confinement effect and surface defects for the PL properties is also investigated in the AlN/ZnO heterostructures. In addition, the photoluminescent (PL) properties of AlN/ZnO CNHs with various AlN shell layers thickness are further discussed.