InterNano Nanomanufacturing Repository
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1523 research outputs found
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Continuous Phase-shift Lithography with a Roll-type Mask and Application to Transparent Conductor Fabrication
No full textWe report the development of a near-field optical nanolithography method using a roll-type phase-shift mask. Sub-wavelength resolution is achieved using near-field exposure of photoresist through a cylindrical phase mask, allowing dynamic and high throughput continuous patterning. As an application, we present the fabrication of a transparent electrode in the form of a metallic wire grid by using the roller-based optical lithography method. To fabricate a mesh-type metal pattern, a specific phase-shift mask was designed and critical experimental parameters were also studied. As a result, a transparent conductor with suitable properties was achieved with a recently built cylindrical phase-shift lithography prototype designed to pattern on 100?mm 2 of substrate area
Lack of Cytochrome Involvement in Long-range Electron Transport through Conductive Biofilms and Nanowires of Geobacter Sulfurreducens
No full textTwo competing models for long-range electron transport through the conductive biofilms and nanowires of Geobacter sulfurreducens exist. In one model electrons are transported via pili that possess delocalized electronic states to function as protein wires with metallic-like conductivity. In the other model electrons are transported by more traditional electron transfer via electron hopping/tunneling between the c-type cytochromes in G. sulfurreducens biofilms and pili. The cytochrome hypothesis was further examined. Quantifying c-type cytochromes in G. sulfurreducens biofilms and pili indicated that there are insufficient cytochromes to account for electron transport through the bulk of the biofilm or pili and demonstrated that there is a negative correlation between cytochrome abundance and biofilm conductivity. Direct imaging using atomic force microscopy revealed that cytochromes were not packed close enough on pili to permit electron hopping/tunneling along the pili. Inactivating cytochromes had no impact on biofilm conductivity. The results of electrochemical gating studies were inconsistent with electron transport via cytochromes. Theoretical considerations suggest that a cytochrome model cannot explain the previously reported response of biofilm conductivity to temperature changes. These multiple lines of evidence, which rely on approaches with different sets of assumptions, demonstrate that the hypothesis that long-range electron transport through G. sulfurreducens biofilms and nanowires can be attributed to electron hopping/tunneling between c-type cytochromes is incorrect. In contrast, these multiple lines of evidence are consistent with long-range electron transport through the biofilms via networks of pili that possess metallic-like conductivity
Integrated Device-Fabric Explorations and Noise Impact and Mitigation in Nanoscale Fabrics
No full textAn integrated device-fabric methodology for evaluating and validating nanoscale computing fabrics is presented. The methodology integrates physical layer assumptions for materials and device structures with accurate 3-D simulations of device electrostatics and operations and circuit-level noise and cascading validations. Electrical characteristics of six different crossed nanowire field-effect transistors (xnwFETs) are simulated and current and capacitance data are obtained. Behavioral models incorporating device data are generated and used in fabric level simulations to evaluate noise implications of devices and sequencing schemes. Device characteristics are found to have different implications for logic “1” and logic “0” noise with faster devices being more (less) resilient to logic “1” (logic “0”) noise. A new noise resilient dynamic sequencing scheme is presented which isolates logic “0” noise events and prevents them from propagating to cascaded circuit stages, thereby enabling faster devices. Performance implications and optimizations for fabrics incorporating the new noise resilient scheme are discussed. The scheme is also analyzed and validated against an external noise source (power supply drooping). These results show that noise resilient nanofabrics can be designed through a combination of device engineering and fabric-level optimizations of the sequencing scheme. Performance optimizations and implications of device and physical layer assumptions on manufacturing are discussed
Development of a Urea Bioprobe Based on Platinized Boron-Doped Diamond Electrodes
No full textUrea (CH6ON2) is one of the main human nitrogen-based metabolic wastes. The concentration of urea in blood lies between 2.57 mM for healthy individuals, and is commonly used as an indicator for several diseases that may alter this value. Spectrophotometric methods are employed for the determination of blood urea concentration during clinical assays. Although these methods are sensitive, they make use of toxic reagents and complex reaction schemes. Therefore, in this research we present the bioelectrochemical determination of urea by the use of the protein urease (E.C.3.1.1.5) along with a nano-platinized boron-doped diamond electrode. This approach has been proven to be efficient and sensitive providing a platform with detection limits of 1.79 mM (S/N=3). The linear range resulted from 1 mM to 25 mM for the determination of urea, and response time of five minutes
Cyclic Brush Polymers by Combining Ring-Expansion Metathesis Polymerization and the ``Grafting from'' Technique
No full textGame Changing Nanomanufacturing Technology: Keeping a Cautious Eye Towards the Future
No full textAssessing the impact of emerging nanomanufacturing science and research requires an objective evaluation of the road to commercialization. In many instances, the path from "lab to fab" is filled with potholes, barriers, and detours, requiring new technologies to demonstrate significant benefits in both cost and performance in order to supplant existing technology and infrastructure. A prime example includes processes and materials being considered for semiconductor integrated circuit manufacturing. While several emerging nanomanufacturing methods, such as directed self assembly (DSA), nanoimprint lithography (NIL), and atomic layer deposition (ALD) are gaining acceptance as a competitive approach for specific steps within the integration sequence, the process for industry adoption remains lengthy and expensive. As a result, the impact of nanomanufacturing methodologies on existing industries and infrastructure has been limited to date. Conversely, the utilization of nanocomposite materials has had a significant impact on numerous industries including aerospace, sporting goods, automotive, and medical devices, enabling functional materials providing higher strength, lighter weight, and lower cost for a broad range of applications. The latter is a better example of a game changing technology providing a completely new approach and infrastructure to solve industry's problem, and further expanding markets, products, and profits.
Also included: NanoBusiness provides review of Nanotech Commercialization Conference - April 3-5 - Durham, NC, FDA Continues Dialogue on 'Nano' Regulation, and Flexible Organic LED (OLED) lighting reaches high energy efficiency thanks to shared research effor
Towards High-Rate Nano-Manufacturing of Gold Nanoparticle Lines
No full textWe prepared lines from Au NPs, using advances in flow-coating methodology, and measured their conductivity on inter-digitated electrodes. These line arrays exhibited an ohmic, linear current-voltage response similar to conductive material. The conductivity of the Au NP lines, measured from top contact configuration (electrode on Au NP lines) is 4 orders of magnitude higher than reported values of Langmuir monolayers of Au NPs. The performance and reproducibility of these lines were confirmed by control experiments and fabricationcharacterization of numerous Au NP line arrays. We also found that these lines can be deposited on non-uniform substrates (Au NP lines on electrode), resulting in shape-conforming conductive paths
Quantum Dot Stability in Cells is Size Dependent
No full textQuantum dots (QDs) are highly fluorescent and photostable, making them excellent tools for imaging. When using these QDs in cells and animals, however, intracellular
biothiols can degrade the QD monolayer compromising function. CHM scientists have developed a label-free method to quantify the intracellular stability of monolayers
on QD surfaces that couples laser desorption/ionization mass spectrometry (LDI-MS) with inductively coupled plasma mass spectrometry (ICP-MS). Using this
new approach they have demonstrated that QD monolayer stability is correlated with both QD particle size and monolayer structure, with proper choice of both particle size and ligand structure required for intracellular stability