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New nanotechnology-based devices are being researched to replace CMOS devices in order to overcome CMOS technology's scaling limitations. However, many such devices exhibit nonmonotonic 1-V characteristics and uncertain properties which lead to the negative differential resistance (NDR) problem and the chaotic performance. This paper proposes two new circuit simulation approaches that can effectively simulate nanotechnology devices with uncertain input sources and negative differential resistance problem. A new tool called NanoSim-RTD is developed based on the proposed new simulation techniques. The experimental results show a speedup of 1.48-37.1 times when compared with existing simulators. Further, this paper demonstrates a new way to design delay-insensitive nanocircuits, and the designs can be verified by using NanoSim-RTD. Index Terms--Asynchronous, bias-based, resonant tunneling devices, stepwise equivalent conductance.

We developed a class of quasi-3D plasmonic crystal that consists of multilayered, regular arrays of subwavelength metal nanostructures. The complex, highly sensitive structure of the optical transmission spectra of these crystals makes them especially well suited for sensing applications. Coupled with quantitative electrodynamics modeling of their optical response, they enable full multiwavelength spectroscopic detection of molecular binding events with sensitivities that correspond to small fractions of a monolayer. The high degree of spatial uniformity of the crystals, formed by a soft nanoimprint technique, provides the ability to image binding events over large areas with micrometer spatial resolution. These features, together with compact form factors, low-cost fabrication procedures, simple readout apparatus, and ability for direct integration into microfluidic networks and arrays, suggest promise for these devices in label-free bioanalytical detection systems. chemical sensing | nanoimprint lithography | surface plasmons | optical transmission spectra

We have prepared nanocomposites of intercalated and exfoliated organosilicates in butadiene rubber (BR) by using a two-stage melt blending process. We used X-ray diffraction and transmission electron microscopy to examine, respectively, the intergallery spacing of the organosilicates and their dispersion in the BR. Marked enhancements in the mechanical and thermal properties of BR occurred when it incorporated, INTRODUCTION Polymer nanocomposites based on the reinforcing of silicate layers derived from montmorillonite and thermoplastic or thermosetting polymers have been developed extensively over the past decade [1-5]. These materials have [...]

The structural, morphological and compositional studies of hydrogenated nanocrystalline silicon carbide (nc-SiC) layers, obtained with a relatively high growth rate through mixing the hydrogen of the plasma with 20% of argon, are reported. These features were found to be consistent with the optical properties of the layers, especially the evolutions of both optical gap and static refractive index.

A systematic study is carried out to locate the critical parameters in the gas phase reaction experiments, which lead to the self-assembly of ZnO/C multilayers outside the Zn nanowires. The analysis shows that the self-assembled multilayer (SAM) formation favors nanowires with polycrystalline native oxide sheath, elevated temperature and CO2 as the reaction gas.

The TNL (Tribo Nanolithography) method in aqueous solution uses the atomic force microscopy as a machining tool for the nanoscale fabrication of silicon. A specially designed cantilever with a diamond tip allows the formation of oxide patterns easily by a simple scratching process. A rectangular structure with a slope can be fabricated by a process in which a thin oxide layer rapidly forms in the substrate at the diamond-tip sample junction along the scanning path of the tip, and, simultaneously, the area uncovered with the oxide layer is being etched. Etching in KOH and HF is conducted to verify corrosion characteristics of oxide.

In Dip Pen Nanolithography (DPN), arbitrary nanoscale chemical patterns can be created by the diffusion of chemicals from the tip of an atomic force microscope (AFM) probe to a surface. This paper describes the design, optimization, fabrication, and testing of an actuated multi-probe DPN array. The probe array consists of 10 thermal bimorph active probes made of silicon nitride and gold. The probes are 300 [micro]m long and the tips are spaced 100 [micro]m apart. An actuation current of 10 mA produces a tip deflection of 8 [micro]m, which is enough to remove individual tips from the surface independent of the adjacent probes. An analytical probe model is presented and used to optimize the design against several possible failure modes. The array is demonstrated by using it to simultaneously write 10 unique octadecanethiol patterns on a gold surface. Pattern linewidth as small as 80 nm has been created at a maximum write speed of 20 [micro]m/sec. By writing multiple, distinctly different patterns in parallel, this device provides a significant improvement in throughput and flexibility over conventional AFM probes in the DPN process. [1137] Index Terms--Atomic force microscope, Dip Pen Nanolithography (DPN), nanolithography, simulation, thermal actuator.

The deposition of a short synthetic peptide by dip-pen nanolithography is presented. The Tapping Mode of atomic force microscope is used for this purpose.

Results from extended time measurements of the two most common ink-substrate combinations used in dip-pen nanolithography (DPN), 16-mercaptohexadeconoic acid (MHDA) and 1-octadecanethiol (ODT) on Au surfaces, using are presented. Studies indicate that measurements with short dwell times are insufficient to determine transport rates for larger features.

The use of direct-write dip-pen nanolithography (DPN) to generate covalently anchored, nanoscale patterns of oligonucleotides on both metallic and insulating substrates is described. Modification of DNA with hexanethiol groups allowed patterning on gold, and oligonucleotides bearing 5'-terminal acrylamide groups could be patterned on derivatized silica. Feature sizes ranging from many micrometers to less than 100 nanometers were achieved, and the resulting patterns exhibited the sequence-specific binding properties of the DNA from which they were composed. The patterns can be used to direct the assembly of individual oligonucleotide-modified particles on a surface, and the deposition of multiple DNA sequences in a single array is demonstrated., Direct-write DPN (1-3) involves the transfer of an ink directly from a coated atomic force microscope (AFM) tip to a substrate of interest. The ability to directly pattern oligonucleotides using [...]

The article studies the theory of the pinning of an air-liquid interface at the feature edge of a template during imprint step of step and flash imprint lithography (SFIL). Results suggest several parameters like residual layer thickness, wettability of the feature edge, applied force on the template, and the radius of curvature of the feature edge, to study the influence of pinning.

A nanoscale decal-transfer lithography (DTL) is described in which the conventional poly(dimethylsiloxane) (PDMS) stamp is alternated with a reusable PDMS-coated nanoscale stamp. This strategy is expected to control the thickness of the transferred PDMS layer by using different types of PDMS.

A simple phenomenological model of the nanografting process with an emphasis on the formation of binary self-assembled monolayers is presented. The simulations demonstrate that the faster the AFM tip displaces adsorbed molecules in a monolayer, the more heterogeneous are the monolayers formed behind the tip, as it allows space and time for the formation of phase-segregated domains.

A scanning probe lithography method known as nanografting in conjunction with knowledge of self-assembly chemistry was used to demonstrate the regulation of the heterogeneity of self-assembled monolayers (SAMs). By varying fabrication parameters, such as shaving speed, and reaction conditions, such as concentration and ratio of the components, the lateral heterogeneity could be adjusted ranging from near molecular mixing to segregated domains of several to tens of nanometers.

Atomic force microscope-based scanned probe oxidation (SPO) nanolithography is carried out on an octadecyl-terminated Si(111) surface to create dot-array patterns under ambient conditions in contact mode. The kinetics investigation indicates that this SPO involves three stages.

A nonlithographic fabrication method of magnetic nanodot array by using porous anodized alumina formed on a glass substrate is studied. It is indicated that the magnetization reversal in the TbFeCo nanodot array occurs by Stoner-Wohlfarth model.

A general technique, Particle Replication In Nonwetting Templates (PRINT), for the fabrication of monodisperse particles with simultaneous control over structure and function is reported. The ability to independently control particle characteristics, such as size, shape, composition, cargo, and surface structure, makes PRINT uniquely suited to fabricate particles for many applications.

The results of a study into factors controlling the quality of nanolithographic imaging. The self-assembled monolayer (SAM) coverage, subsequent postetch pattern definition and minimum feature size all depend on the quality of the Au substrate used in material mask atomic nanolithographic experiments.

The manner in which Dip-Pen Nanolithography (DPN) can be used to study heterogeneous nucleation in thin films is described. DPN-generated surface templates offer a powerful means for controlling phase-separation and pattern formation in thin films containing conjugated polymers, without the need for masks, stamps or extreme UV light sources.

The research published in nanofabrication during the interval from 1999 to mid-2004 is discussed and specific techniques capable of patterning a substrate with features less than or equal to 100 nm in both lateral and vertical dimensions are demonstrated. The development of microelectric circuits with < 100-nm-scale features is rapidly proceeding by extensions of existing, conventional photolithographic techniques.

A technique based on coherent control for the optical manipulation of deposition patterns in nanofabrication with neutral atomic beams is described. The theory optical nanolithography with bichromatic fields is then applied to the deposition of rubidium Rydberg atoms on surfaces.

A novel electrochemical strategy to nanoparticle-based catalyst design using the recently developed underpotential deposition (UPD) redox replacement technique is presented. The results demonstrate the ultrathin Pt coating effects efficiently and behaves as the nanostructured monometallic Pt for electrocatalystic oxygen reduction, and shows size-dependent, tunable electrocatalytic ability.

Nanocrystalline SnO2 particles are synthesized by a simple sol-gel method. The structural and optical properties of these SnO2 particles are investigated using X-ray powder diffraction, transmission electron microscopy, UV- visible absorption, and photoluminescence spectroscopy.

A novel chemical method has been developed for synthesizing Au nanoparticles using sucrose as the raw material based on gold seeding formation in the solid phase and seeding growth in aqueous solution. The results indicate that the synthesized gold nanoparticles can be used to self-assemble monolayers and to fabricate biochemical sensors based on surface plasmon resonance effect.

The pulse radiolysis techniques are used to study the reduction of methyl viologen ions, MV(super +2), absorbed on SiO2 nanoparticles in N2O saturated colloidal suspensions. The efficiency of scavenging the electron decreases with increasing particle size, due to the increased fraction of charge recombination and trapping that occurs in the large particles, and it is estimated that no electrons will reach the surface of particles larger than 30 nm in diameter.

Without the constraint of using an enzyme, which is tethered to an Atomic Force Microscope (AFM), a proof-of-principle of an enzyme-catalyzed reaction on an immobilized substrate, a self-assembled monolayer, that present a terminal oligonucleotide, is presented.

The photoactive components of common Novolac-based positive photoresists are derivatives of 2-diazo-1(2H)-Napthalenone. The UV radiation is induced on the Wolf rearrangement of alpha-diazocarbonyl compounds and is analyzed that the same excitation energy can be achieved by simultaneous absorbance of two red/NIR photons.

A study is conducted to show how heteromolecular interfaces between electron donors and acceptors of respectively functionalized nanoparticles form a rectifier. It is suggested that electronic structures for molecular rectifiers containing electron acceptor and donor groups might be assembled alternatively through appropriate nanoscale architectures using sequential deposition of functionalized nanoparticles.

Intense laser based molecular optics can be used as a route to nanoscale processing of substrates with unique advantages. A narrower and longer features could be created with high power lasers with a grazing angle of incidence between the laser and molecular beams to create wires 100 mu m long with 100 W continuous wave laser.

A multistep approach to biomolecular assembly is presented, which combines scanning probe nanolithography (SPN) with chemoselective protein-to-surface linkers to create nanometric chemical templates for fabricating virus arrays. The assembly of these arrays introduces unique target chemical groups on the virus surface and design a chemoselective linker and reaction scheme to covalently bind the virus onto a patterned chemical template created by SPN.

Two lithographic methods, namely dynamic plowing lithography (DPL) and force displacement curves (FDI) are compared. DPL is faster and more practical than FDI, but DPL is the creation of undesirable remarkably large border walls surrounding the lithographed structures.

The multitude of nanoparticle structural motifs accessible using nanosphere lithography (NSL) is demonstrated. The possible applications of these nanostructures as data storage media, components for future nanoelectronic systems, and substrates for surface-enhanced Raman spectroscopy are discussed.

Fabrication techniques for replicating nanoscale structures are increasingly becoming dependent on micro- and nanofabrication tools, which are expensive in today's world. Hence, achieving rapid, cost-effective, and large-scale nanorfabrication is an [...]

Gold nanoparticles are grabbing increased attention in the last few years due to their optical response in biological assays, detection, labeling, and sensing. In this regard, the important issue of [...]

According to the 2007 report of the International Technology Roadmap for Semiconductors, the future reduction in manufactured pitch size will require the application of techniques other than optical litography techniques. [...]

In recent times, nanotechnology has been found to offer a number of advantages to new products developed using rapid prototyping and manufacturing. Essentially, the performance of standard materials employed for [...]