Highly-ordered arrays of parallel carbon nanotubes were grown by pyrolysis acetylene on cobalt within a hexagonal close-packed nanochannel alumina template at 650 °C. The are characterized narrow size distribution, large scale periodicity, and high densities. Using this method ordered with diameters from 10 nm to several hundred lengths up 100 μm can be produced. level ordering uniformity in these is useful for applications data storage, field emission displays sensors, offers the prospect...

A novel way of engineering DNA molecules involves substituting the imino proton each base pair with a metal ion to obtain $M$-DNA altered electronic properties. We report first direct evidence metalliclike conduction through $15\ensuremath{\mu}\mathrm{m}$ long $M$-DNA. In contrast, measurements on $B$-DNA give semiconducting behavior few hundred meV band gap at room temperature. The drastic change conductivity points new degree freedom in development future molecular electronics utilizing...

Electronic transport measurements were performed on Y-junction carbon nanotubes. These novel junctions contain a large diameter tube branched into smaller ones. Independent using good quality contacts both individual Y and many in parallel show intrinsic nonlinear reproducible rectifying behavior at room temperature. The results modeled classic interface physics for junction with an abrupt change band gap due to the diameter. tubes represent new heterojunctions nanoelectronics.

A microscopic model describing the electronic structure of carbon nanotubes formed from two-dimensional disordered graphite sheets is presented. The strong electronic-lattice coupling states near Fermi energy shown to result in formation an gap. predicts that gap these tubes inversely proportional diameter with a larger magnitude than crystalline tubes. Our results are be good agreement experimental data for containing considerable structural defects.

This paper studies the relation between photoexcitation of a single-walled carbon nanotube (SWNT) based device, and its THz output power in context photoconductive (PC) switching photomixing. A detailed approach calculating for such device describes effect each parameter on performance PC switch highlights design dependent achievable limits. numerical assessment, with typical values parameter, shows that-subject to thermal stability device-SWNT can improve by almost two orders magnitudes...

Periodic nanometer-scale patterning of sub-100 nm catalyst particles on silicon is used to grow carbon nanotubes via chemical vapor deposition from methane. The resulting structures consist very straight individual single-walled that are preferentially aligned along perpendicular directions in the plane (see figure).

The hole carrier concentration of semiconducting carbon nanotubes is calculated as a function tube diameter based on self-doping mechanism caused by curvature induced charge redistribution the bonding orbitals. results show that nanotube inversely proportional to and agree well with field-effect measurements Raman spectroscopy pristine nanotubes.

Single-walled carbon nanotubes were assembled into large-area arrays of nanoscale rings on silicon via direct patterning with a self-assembled colloidal polystyrene sphere mask. Nanotubes from liquid suspension gathered at the base each in mask to form rings, and resulting consisted well-ordered nanotube diameters 203+/-21 nm 97+/-14 for formed 780 450 spheres, respectively. Ring heights found be 4.7+/-1.8 5.9+/-1.4 masks, A first-order geometric model was proposed account observed ring...

Electronic transport properties of nanoscale networks composed interconnected molecules/gold nanoclusters are examined via first-principles plane wave scattering density functional theory-based simulations. Au-molecular (benzene/alkanedithiol) junctions and networks, connected in linear chains Y-, H- ring-shaped were studied. Molecular orbital calculations show HOMO (highest-occupied-molecular-orbital)-LUMO (lowest-unoccupied-molecular-orbital) gaps decreased with length, indicating barrier...

Electronic transport in Y-junction carbon nanotubes was examined as a function of temperature. Rectifying behavior observed from 10to300K with the conductance displaying power-law dependencies on temperature and applied bias. The data are consistent models for tunneling between two tube segments but display asymmetric exponents depending bias polarity. asymmetry is found to be essentially independent can understood lack inversion symmetry geometry, which creates unique type mesoscopic...

Controlled growth and precise placement of carbon nanotubes (CNTs) are two vital capabilities for the practical implementation CNT device designs. This article presents an overview our research activities aimed at using CVD template to both structure precisely align CNTs into functional system building blocks. Fabrication results on highly-ordered arrays Y-junction described along with outline their novel physical properties that could lead unique applications.

Electronic transport through self‐assembled networks consisting of colloidal gold particles interconnected with thiolated alkane molecules is studied using a combination broad area and scanning probe microscope‐based measurements. The molecule–gold nanoparticle ratio and/or type used to alter electronic paths the network allow resistance be controllably tuned by several orders magnitude (∼10 5 –10 11 ohms for structures studied). Local probing imaging via atomic force microscopy able detect...

Planetary ball-milled zinc oxide (ZnO) nanoparticle suspensions (nanoinks) were used to produce thin film chemiresistive gas sensors that operate at room temperature. By varying milling or grinding parameters (speed, time, and solvent) different with tunable particle sizes porosity fabricated tested dry air/oxygen against hydrogen, argon, methane target species, in addition relative humidity, under ambient light conditions. Grinding speeds of up 1000 rpm produced RMS roughness below 100 nm,...

Photomixers commonly used to generate THz radiation cannot more than a few microwatts of power and therefore enhancement remains as challenge. New materials such carbon nanotubes offer set properties that possess the potential for photomixing. This paper evaluates these key photomixing purposes estimates increase in output comparison conventional LT-GaAs photomixers.

A modern and concise treatment of the solid state electronic devices that are fundamental to systems information technology is provided in this book. The main comprise semiconductor integrated circuits covered a clear manner accessible wide range scientific engineering disciplines impacted by technology. Catering wider audience becoming increasingly important as field materials becomes more interdisciplinary, with applications biology, chemistry electro-mechanical (to name few) prevalent....

Nanoscale clusters of C60 fullerene molecules arranged in regular arrays were synthesized on silicon and mica substrates. The grown by adsorption onto gold dots formed using a self-assembled colloidal mask, whose openings precisely controlled thermal annealing. Self-assembled monolayers thiol used to create well-defined gap between the fullerenes surface. Using this approach, large periodically nanoparticles can be wide range substrates, with diameters that are tunable from less than 10 nm...

Nanowriting was used to directly pattern carbon nanotube (CNT) catalyst solution with a scanning probe microscope. Glass nanopipettes filled iron-based solutions were scanned in predefined patterns using contact mode atomic force microscopy on silicon/silicon dioxide substrates create nanoscale surface distributions. Chemical vapor deposition methane feedstock at 900°C produced single-walled CNTs the patterned regions. Examination of patterning and growth conditions provided insight into...