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The preparation and electrical properties of high-temperature superconductor nanowire arrays are reported for the first time. YBa2Cu3O(7-delta) nanowires with widths as small as 10 nm (much smaller than the magnetic penetration depth) and lengths up to 200 microm are studied by four-point electrical measurements. All nanowires exhibit a superconducting transition above liquid nitrogen temperature and a transition temperature width that depends strongly upon the nanowire dimensions. Nanowire size effects are systematically studied, and the results are modeled satisfactorily using phase-slip theories that generate reasonable parameters. These nanowires can function as superconducting nanoelectronic components over much wider temperature ranges as compared to conventional superconductor nanowires.

Statistical numbers of field-effect transistors (FETs) were fabricated from a circuit of 17-nm-wide, 34-nm-pitch Si nanowires boron doped at a level of 10(18) cm-3. Top-gated 4-microm-wide Si nanowire p-FETs yielded low off-currents (approximately 10(-12) A), high on/off ratios (10(5)-10(6)), good on current values (30 microA/microm), high mobilities (approximately 100 cm2/V-s), and low subthreshold swing values (approximately 80 mV/decade between 10(-12) and 10(-10) A increasing to 200 mV/decade between 10(-10)-10(-8) A).

In this paper, we demonstrate a template-free, site-specific, and scalable electrochemical method for the fabrication of individually addressable polyaniline nanoframework electrode junctions in a parallel-oriented array. These polyaniline nanoframeworks, which are composed of numerous intercrossing polyaniline nanowires that have uniform diameters ranging from 40 to 80 nm, can be used for the chemical sensing of HCl and NH_3 gases and ethanol vapor and for sensing the pH of aqueous NaCl solutions.

The local charge carrier density of graphene can exhibit significant and highly localized variations that arise from the interaction between graphene and the local environment, such as adsorbed water, or a supporting substrate. However, it has been difficult to correlate such spatial variations with individual impurity sites. By trapping (under graphene) nanometer-sized water clusters on the atomically well-defined Au(111) substrate, we utilize scanning tunneling microscopy and spectroscopy to characterize the local doping influence of individual water clusters on graphene. We find that water clusters, predominantly nucleated at the atomic steps of Au(111), induce strong and highly localized electron doping in graphene. A positive correlation is observed between the water cluster size and the local doping level, in support of the recently proposed electrostatic-field-mediated doping mechanism. Our findings quantitatively demonstrate the importance of substrate-adsorbed water on the electronic properties of graphene.

We report on the scanning tunneling microscopy study of a new class of corrugations in exfoliated monolayer graphene sheets, that is, wrinkles approximately 10 nm in width and approximately 3 nm in height. We found such corrugations to be ubiquitous in graphene and have distinctly different properties when compared to other regions of graphene. In particular, a "three-for-six" triangular pattern of atoms is exclusively and consistently observed on wrinkles, suggesting the local curvature of the wrinkle provides a sufficient perturbation to break the 6-fold symmetry of the graphene lattice. Through scanning tunneling spectroscopy, we further demonstrate that the wrinkles have lower electrical conductance and are characterized by the presence of midgap states, which is in agreement with recent theoretical predictions. The observed wrinkles are likely important for understanding the electrical properties of graphene.

Electrolyte transport through an array of 20 nm wide, 20 microm long SiO(2) nanofluidic transistors is described. At sufficiently low ionic strength, the Debye screening length exceeds the channel width, and ion transport is limited by the negatively charged channel surfaces. At source-drain biases5 V, the current exhibits a sharp, nonlinear increase, with a 20-50-fold conductance enhancement. This behavior is attributed to a breakdown of the zero-slip condition. Implications for energy conversion devices are discussed.

We report a general method for reliably fabricating quasi-one-dimensional superconducting nanowire arrays, with good control over nanowire cross section and length, and with full compatibility with device processing methods. We investigate Nb nanowires with individual nanowire cross sectional areas that range from bulklike to 10 x 11 nm, and with lengths from 1 to 100 microm. Nanowire size effects are systematically studied. In particular, a comprehensive investigation of influence of nanowire length on superconductivity is reported for the first time. All results are interpreted within the context of phase-slip models.

High density metal cross bars at 17 nm half-pitch were fabricated by nanoimprint lithography. Utilizing the superlattice nanowire pattern transfer technique, a 300-layer GaAs/AlGaAs superlattice was employed to produce an array of 150 Si nanowires (15 nm wide at 34 nm pitch) as an imprinting mold. A successful reproduction of the Si nanowire pattern was demonstrated. Furthermore, a cross-bar platinum nanowire array with a cell density of approximately 100 Gbit/cm(2) was fabricated by two consecutive imprinting processes.