Noble-metal nanoparticles embedded in dielectric matrices are considered to have practical applications in ultrafast all-optical switching devices owing to their enhanced third-order nonlinear susceptibility, especially near the surface-plasmon-resonance (SPR) frequency. Here we present the use of a microreactor approach to the fabrication of a self-organized photosensitive gold nanoparticle chain encapsulated in a dielectric nanowire. Such a hybrid nanowire shows pronounced SPR absorption. More remarkably, a strong wavelength-dependent and reversible photoresponse has been demonstrated in a two-terminal device using an ensemble of gold nanopeapodded silica nanowires under light illumination, whereas no photoresponse was observed for the plain silica nanowires. These results show the potential of using gold nanopeapodded silica nanowires as wavelength-controlled optical nanoswitches. The microreactor approach can be applied to the preparation of a range of hybrid metal-dielectric one-dimensional nanostructures that can be used as functional building blocks for nanoscale waveguiding devices, sensors and optoelectronics.

In this study, the growth of high density single-crystalline ZnO nanowires on patterned ZnO:Ga/SiO(2)/Si templates was reported. We also adsorbed Au nanoparticles onto nanowire surfaces and fabricated ZnO nanowire CO sensors. With 50 ppm CO gas, it was found that we could enhance the device sensitivities at 350 °C from 4.2% to 46.5% by the adsorption of Au nanoparticles. It was also found that measured sensitivities were around 30%, 37%, 46.5% and 53% when concentration of the injected CO gas was 5, 20, 50 and 100 ppm, respectively.

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In this study, we report the growth and characterization of lateral ZnO nanowires (NWs) on ZnO:Ga/glass templates. Using x-ray diffraction and micro-Raman spectroscopy, it was found that crystal quality of the as-grown ZnO NWs is good. It was also found that the average length and average diameter of the laterally grown ZnO NWs were 5 µm and 30 nm, respectively. A vacuum pressure sensor was then fabricated using a single NW bridging across two electrodes. By measuring the current-voltage characteristics of the samples at low pressure, we found that the currents were of 17, 34.28, 57.37 and 96.06 nA for the ZnO NW measured at 1 × 10(-3) Torr, 1 × 10(-4) Torr, 3 × 10(-5) Torr and 5 × 10(-6) Torr, respectively. These values suggest that the laterally grown ZnO NWs prepared in this study are potentially useful for vacuum pressure sensing.

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