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The uniformity of the pore size and the morphology of nano-porous anodic alumina (nano-PAA) can be improved by a pore-widening process. The evolution of the pore diameter and the morphology was investigated in real time. Phosphoric acid solution (3wt%) was used as the etchant to chemically enlarge the pores of a nano-PAA prepared with oxalic acid. It is found that the pore-widening is carrying out simultaneously both on top-view and cross-section. From the top-view analysis, the pore diameter gradually enlarges with the increasing of etching time. However, such enlarging rate varies with the multilayer structure of the pore wall. From the cross-section analysis, the pores walls of a multilayered amorphous compound are etched in a stage-by-stage mode until almost everything is etched away. The pore-widening procedure on the upper portion is completed earlier respect to the lower portion, after some time the pore-widening becomes uniform along the axial direction. If the etching is maintained, hexagonal pore walls will be destroyed and split into ultrahigh aspect ratio nanowires due to the etching anisotropy, and finally completely dissolved. Combining analyses in the depth direction with stereoscopic 3D imaging the results clarify the pore-widening mechanism in 3D nano-PAA.

We report the current-voltage (I{V ) characteristics of individual polypyrrole nanotubes and poly(3,4ethylenedioxythiophene) (PEDOT) nanowires in a temperature range from 300 K to 2 K. Considering the complex structures of such quasi-one-dimensional systems with an array of ordered conductive regions separated by disordered barriers, we use the extended ∞uctuation-induced tunneling (FIT) and thermal excitation model (Kaiser expression) to flt the temperature and electric-fleld dependent I{V curves. It is found that the I{V data measured at higher temperatures or higher voltages can be well fltted by the Kaiser expression. However, the low-temperature data around the zero bias clearly deviate from those obtained from this model. The deviation (or zero-bias conductance suppression) could be possibly ascribed to the occurrence of the Coulomb-gap in the density of states near the Femi level and/or the enhancement of electron-electron interaction resulting from nanosize efiects, which have been revealed in the previous studies on low-temperature electronic transport in conducting polymer fllms, pellets and nanostructures. In addition, similar I{V characteristics and deviation are also observed in an isolated K0:27MnO2 nanowire.

We report the current–voltage (I–V) characteristics and electrical conductivity of individual template-synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires (190 ± 6 nm in diameter and ort = 11.2 ± 2 Ω−1cm-1) over a wide temperature range from 300 to 10K. With lowering temperature, the I – V characteristics become nonlinear around 50K, and a clear Coulomb gap-like structure appears in the differential conductance (dl/dV) spectra. The temperature dependence of the resistance below 70K follows inR ∞ T-1/2, which can be interpreted as Efros–Shklovskii hopping conduction in the presence of a Coulomb gap. In addition, the influences of measurement methods such as the applied bias voltage magnitude, the two-probe and four-probe techniques used in the resistance measurements are also reported and discussed.

This paper studies the electronic transport in an individual helically twisted CdS nanowire rope, on which platinum microleads are attached by focused-ion beam deposition. The current–voltage (I –V) characteristics are nonlinear from 300 down to 60 K. Some step-like structures in the I – V curves and oscillation peaks in the differential conductance (dI/dV - V) curves have been observed even at room temperature. It proposes that the observed behaviour can be attributed to Coulomb-blockade transport in the one-dimensional CdS nanowires with diameters of 6–10 nm.

The extraordinary light transmission through a 200-nm thick gold film when passing through different subwavelength hole arrays is observed experimentally. The sample is fabricated by electron beam lithography and reactive ion etching system. A comparison between light transmissions shows that the hole shape changing from rectangular to diamond strongly affects the transmission intensity although both structures possess the same lattice constant of 600 nm. Moreover, the position of the transmission maximum undergoes a spectral red-shift of about 63 nm. Numerical simulations by using a transfer matrix method reproduce the observed transmission spectrum quite well.

Conducting microtubes (0.4–0.5μm in outer diameter) made of polypyrrole (PPy) doped with p-toluene sulfonic acid (PTSA) were synthesized by a self-assembly method. We report the electrical conductivity of an individual PPy microtube, on which a pair of platinum micro-leads was fabricated by focused ion beam deposition. The measured room-temperature conductivity of the individual PPy microtube was 0.29S/cm, which is comparable to that of template-synthesized PPy micro/nanotubes. The temperature dependence of conductivity of the individual microtube follows the three-dimensional variable-range hopping (3D VRH) model.

A thermodynamic theory about the dependence of morphology of SiOx nanowires on the super-saturation of alloy liquid droplets has been proposed on the basis of the vapour-liquid-solid growth mechanism and has been supported experimentally. By changing the Si concentration in the Au-Si liquid droplets formed on the Au-coated Si substrate, firework-, tulip- and bud-shaped SiOx nanowires were synthesized by a thermal evaporation method and distributed concentrically around some void defects in the Si substrate. Voids were formed underneath the surface of the Si substrate during the thermal evaporation at 850°C and resulted in the Si-concentration deficient thus different saturation of Au-Si droplets. Electron microscopy analysis showed that the nanowires had an amorphous structure and were terminated by Au-Si particles.

Two kinds of subwavelength hole arrays in metallic films are designed to verify the important role of the periodicity in enhanced transmission of light. The measured optical spectra show that the quasiperiodic hole arrays exhibit an enhanced transmission peak centred at 707 nm with a transmission intensity of about 20%, while no plasmon resonance peak is found for the amorphous hole arrays. When the hole diameter decreases in the quasiperiodic structure, the position of the transmission peak shifts slightly, and the transmittance drops. These phenomena indicate the important role of the long-range structural order (particularly the periodicity) in assisting the coupling of incident light wave with the surface plasmon modes of the metallic structures.

A method of manufacturing two-dimensional photonic crystals on several kinds of semiconductor materials in near infrared region by a focused ion beam is introduced, and the corresponding fabrication results are presented and show that the obtained parameters of fabricated photonic crystals are identical with the designed ones. Using the tunable laser source, the spectra of the fabricated passive photonic crystal and the active photonic crystal are measured. The experiment demonstrates that the focused ion-beam can be used to fabricate the perfect two-dimensional photonic crystals and their devices.

Two-dimensional photonic crystals in near infrared region were fabricated by using the focused ion beam (FIB) method and the method of electron-beam lithography (EBL) combined with dry etching. Both methods can fabricate perfect crystals, the method of FIB is simple,the other is more complicated. It is shown that the material with the photonic crystal fabricated by FIB has no fluorescence,on the other hand, the small-lattice photonic crystal made by EBL combined with dry etching can enhance the extraction efficiency two folds, though the photonic crystal has some disorder. The mechanisms of the enhanced-emission and the absence of emission are also discussed.

Nano-sized graphite patterns were obtained by tailoring graphite sheets using different methods. With focused ion beam etching we are able to produce grooves of minimum width ～ 30 nm. However, at the edges of the grooves there deposit with Ga-C compound which prevents the easy cleavage of the graphite sheets. With electron beam lithography and reactive ion etching techniques we are able to produce graphite patterns of sizes down to 50 nm. Three different types of masks are tested, and the results are compared and discussed.

In the emerging field of nanobiotechnology, further downsizing the fluidic channels to the nanometer scale is attractive for both fundamental studies and technical applications. The insulation Silicon nitride membrane nanofluidic channel array which have width#8764;75nm and depth#8764; 100nm and length 50#956;m were created by focused-ion- beam instrument, the#955;--DNA molecules were put inside them and the dynamic characteristics were initial studied, a fluorescence microscopy was used to observe the images. We observed#955;--DNA moved inside the nanotrenches which dealt with activating reagent Brij aqueous solution only by capillary force,this will help us to understand more DNA dynamics characteristics and more information about single biomolecule transporting through a nanopore,.