Large-scale highly oriented ZnO nanorod arrays were directly grown on zinc foil through a simple hydrothermal reaction of Zn foil with aqueous ammonia at 100 °C. The products were characterized with X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. It was found that the ZnO nanorods were single crystalline with the wurtzite structure and grown in the [0001] direction, and have a controllable diameter in the range of 250-100 nm with lengths of up to 4.0 µm by varying the growth time. The ammonia plays a key role in the formation of ZnO nanorod arrays, and a possible mechanism is also proposed to account for the growth of the ZnO nanorod arrays. The ZnO nanorod arrays exhibited a UV emission with peak at 396 nm and a blue green emission with a peak at 488 nm. The UV and blue green emissions are considered to originate from the exciton transition and the transition between the oxygen vacancy and interstitial oxygen, respectively. In addition, the UV and blue green emission intensities can be adjusted by changing the growth time.

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Nanosheets, nanobelts, and ultralong nanobelt arrays with honeycomb-like micropatterns of ZnSe were synthesized via a solvothermal reaction of Zn with Se and KBH(4) in ethylenediamine at 200 degrees C for 24 h and subsequent annealing. The control over these nanostructures with different morphologies was achieved by adjusting the KBH(4)/Se molar ratio. The role of KBH(4) in the formation of ZnSe(en)(0.5) nanobelts with different length-to-width ratios was investigated, and a possible mechanism was also proposed to account for the growth and conversion of these precursor nanostructures into ZnSe nanostructures. Current-voltage behaviors of the ultralong nanobelt arrays with honeycomb-like micropatterns were investigated. In addition, variable-aspect ratio ZnS nanosheets and nanowires were also synthesized by adjusting the KBH(4)/thiourea molar ratio in the Zn-thiourea-KBH(4)-ethylenediamine solvothermal system. The results suggest that this method may be employed for the controllable synthesis of other II-VI semiconductor nanostructures such as ZnTe, NiS, MnS, and so forth and provides opportunities for both fundamental research and technological applications.