Based on the achievement of synthesis of ZnO nanowires in mass production, ZnO nanowires gas sensors were fabricated with microelectromechanical system technology and ethanol-sensing characteristics were investigated. The sensor exhibited high sensitivity and fast response to ethanol gas at a work temperature of 300 °C. Our results demonstrate the potential application of ZnO nanowires for fabricating highly sensitive gas sensors.

Tetrapod-like zinc oxide (ZnO) nanostructures can be synthesized by rapid heating metal zinc pellet at 900 °C under air ambient. Catalyst, vacuum, and carrying gas are not necessary, and more importantly, it is a volcanic process for rapid and mass production. The turn-on field of the synthesized tetrapod-like ZnO nanostructures is found to be as low as 1.6 V/μm at the current density of 1 μA/cm2. These ZnO nanostructures are technologically useful for vacuum electron devices because they can be easily and economically synthesized and deposited on large substrates.

We report on the microwave response properties of the ZnO nanowire-polyester composites fabricated into a planar plate with the area of 180×180 mm2 and the thickness of about 1 mm. Strong microwave absorption has been observed in X band and the maximum absorption is enhanced as the concentration of the nanowires increases in the composites. Both the low complex permittivity and the low dissipation of the pure nanowires demonstrate the pure nanowires are low-loss materials for microwave absorption in X band. The strong absorption is related to interfacial multipoles at the interface between the polyester and the ZnO nanowires, a high surface-to-volume ratio and a similar shape of the nanowires to antenna.

Structural and electrical characteristics of the metal–insulator–semiconductor (MIS) structures of Al/Al2O3/Si containing Ge nanoclusters are experimentally demonstrated. Secondary ion mass spectroscopy results indicate the out-diffusion of Ge after annealing at 800 °C in N2 ambient for 30 min. An increment of leakage current is observed due to the out-diffusion of Ge. Capacitance–voltage studies indicate that annealing can effectively passivate the negatively charged trapping centers. Memory effect of the Ge nanoclusters is verified by the hysteresis in the C–V curves in the annealed sample.

Metal–insulator–semiconductor (MIS) structures containing Ge nanocrystals embedded in high permittivity dielectrics (ZrO2/Al2O3) are fabricated by electron-beam evaporation method. Capacitance–voltage (C–V) and I–V characteristics of the fabricated MIS structures are investigated in the dark and under illumination. Charge storing and negative photoconductivity effects of the Ge nanocrystals are experimentally demonstrated by the hysteresis in the C–V curves and the decrease of the current under illumination at a given voltage, respectively.