Core/single-crystal-shell nanospheres are constructed from a poly-(N-vinyl- 2-pyrrolidone) (PVP)-modified silica core with an outer layer of single-crystal iron oxide shell. The nanospheres show outstanding release-and-zero-release characteristics via the addition and removal, respectively, of an external high-frequency magnetic field.

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The effect of pulsed laser annealing (PLA) on the photoluminescence (PL) properties of ZnO nanorods was investigated. As the fluence of pulsed laser increases, the UV PL in ZnO nanorods shows a general increasing trend, except at a range of fluences from 10 to 70 mJ/cm 2 . It is found that the treatment with the PLA at the fluence of 70 mJ/cm 2 leads to a larger improvement of crystalline properties than that with rapid thermal annealing (RTA). The relationship between PL intensity and fluence of pulsed lasers can be well explained by a combination of the deterioration in surface crystallinity and the increased donor densities after PLA.

Photoelectronic characteristics are investigated in well-aligned aluminum-coated ZnO nanorods ͑Al 2 O 3 /ZnO nanocables͒ grown on Si substrates buffered with ZnO film at a low temperature. Photoluminescence measurement indicates that a strong blue emission peak at ϳ450 nm appears at 400 and 600°C in O 2 and N 2 atmospheres, respectively. A 30ϫ enhancement of the relative intensity ratio of blue emission ͑I B ͒ to ultraviolet emission ͑I UV ͒ has been observed for the Al 2 O 3 /ZnO nanocables. Highresolution transmission electron microscopy and X-ray photoelectron spectroscopy analyses reveal that the origin of the strong blue emission can be attributed to the structure transition and cleavage of the oxygen-hydrogen bond ͑OH͒ of the Al 2 O 3 /ZnO nanocable, which leads to the formation of singly ionized oxygen vacancies ͑Al-O • ͒.

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