Carbon Nanotube Technology Research Articles

Carbon nanotube production and application in energy storage

ABSTRACTIn order to enhance the application of carbon nanotubes (CNTs) in electrochemical energy storage, we reviewed the production and purification technology of CNTs, as well as the application in Li‐ion battery, supercapacitors (SC), and asymmetric SC. In detail, the formation mechanism, the effects influencing the diameter, diameter distribution, yield and growth rate of CNTs, and the reactor technology for scale up were thoroughly discussed. And the purity, the type of impurities and factors influencing the formation of impurities, and the purification method of CNTs were summarized on the basis of the requirements in the electrochemical use. Finally, the performance of CNTs used in energy storage systems and the challenge for the commercialization were analyzed. The review provides abundant information for better understanding of the relationship between the structure, property of CNTs and its performance. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Nanowelding configuration between carbon nanotubes in axial direction

Interconnect technology of carbon nanotubes (CNTs) is essential for functional devices. However, difficulty in the fabrication of the interface between carbon nanotube (CNT) and CNT in axial direction, hindered the quality of connection and practical applications of electrical devices. Also, investigation of dynamic evolution of connection configuration about nanowelding is still lacking. In order to analyze the nanowelding configuration between CNTs in axial direction, the different connection cases are investigated using molecular dynamics simulation. Simulation results show that the nanowelding process could be accomplished at a lower temperature than the melting point of the bulk solder and the CNTs are connected with solder joints of nodule shape. It is also found that metal atoms are captured and dragged into nanotube to form the core filling structures of nanowires during nanowelding. Also, the connection configuration shows that Ag atoms diffuse along the outer walls of SWNTs with the dominant mechanism of capillary wetting, which would increase the contact length to improve the mechanical strength.

ANALYSIS OF A NOVEL FULL ADDER DESIGNED FOR IMPLEMENTING IN CARBONE NANOTUBE TECHNOLOGY

A novel low power-delay product full adder circuit is presented in this paper. A new approach is used in order to design full-swing full adder with low number of transistors. The proposed full adder is implemented in MOSFET-like Carbon nanotube technology and the layout is provided based on standard 32 nm technology from MOSIS. The simulation results using HSPICE show that, there are substantial improvements in both power and performance of the proposed circuit compared to latest designs. In addition, the proposed circuit has been implemented in conventional 32 nm process to estimate the advantages of using carbon-based transistors in digital designs over conventional silicon technology. The proposed circuit can be applied in ultra low power and very high speed applications.

Carbon Nanotube Research: Past and Future

In this paper, my experience of over 30 years in carbon materials and carbon nanotube (CNT) researches is reported. Moreover, an overview of the background of the development of CNT synthesis, the present status of CNT science and technology, and the future prospect of CNTs are described.

A novel, efficient CNTFET Galois design as a basic ternary-valued logic field

This paper presents arithmetic operations, including addition and multiplication, in the ternary Galois field through carbon nanotube field-effect transistors (CNTFETs). Ternary logics have received considerable attention among all the multiple-valued logics. Multiple-valued logics are an alternative to common-practice binary logic, which mostly has been expanded from ternary (three-valued) logic. CNTFETs are used to improve Galois field circuit performance. In this study, a novel design technique for ternary logic gates based on CNTFETs was used to design novel, efficient Galois field circuits that will be compared with the existing resistive-load CNTFET circuit designs. In this paper, by using carbon nanotube technology and avoiding the use of resistors, we will reduce power consumption and delay, and will also achieve a better product. Simulation results using HSPICE illustrate substantial improvement in speed and power consumption.

Chemistry of Carbon Nanotubes for Everyone

Carbon nanotubes (CNTs) have the extraordinary potential to change our lives by improving existing products and enabling new ones. Current and future research and industrial workforce professionals are very likely to encounter some aspects of nanotechnology including CNT science and technology in their education or profession. The simple structure and interesting chemistry of CNTs make their inclusion in an undergraduate curriculum appropriate. An overview of the chemistry of CNTs is presented starting with a brief history followed by discussions on chemical structure, exceptional properties, potential applications, nature of technological challenges, and possible solutions that will expand the optimal utilization of these materials in the near future. This article is intended to be a starting point for developing a variety of CNT-based undergraduate projects.

Carbon Nanotube-Based CMOS Gas Sensor IC: Monolithic Integration of Pd Decorated Carbon Nanotube Network on a CMOS Chip and Its Hydrogen Sensing

The integration of carbon nanotube (CNT)-based sensor and readout complementary metal-oxide-semiconductor integrated chip (CMOS IC) to detect hydrogen gas in a single chip is presented. First, we have fabricated the CMOS IC using the standard 0.35-μm CMOS process. Then, we have built 8 × 8 CNT-based sensor cells on it using a proposed tractable postprocessing strategy and judicious electrode scheme. The fabricated sensor IC can operate down to 10-ppm concentration of hydrogen in air as a hydrogen sensor. This paper is expected to have a major impact upon the integration of the CNT technology with CMOS technology and be extended to the development of CMOS IC integrated with various nanomaterials.

Research the Al Material Reinforced by CNT(Carbon Nanotubes)

This paper using high energy ball milling(HEM), researched the technology of preparation of Al compound material reinforced by CNT. Researched the different milling time, rotary speed, amount of CNT and sinter technology on properties of hardness and density. Preparation the Al-CNT at milling time about 30 to 100 min, rotational speed is about 300-600/rpm.the wt% of CNT is 0-5%, Analyzed the XRD patterns、SEM and STM micrograph, the results showed the Al material could be reinforced by CNT using HEM. the hardness of Al-CNT is 75 HB and the density is 2.65 g/cm3 when milling 90 min and CNT 3%.

Design and Analysis of a New Carbon Nanotube Full Adder Cell

A novel full adder circuit is presented. The main aim is to reduce power delay product (PDP) in the presented full adder cell. A new method is used in order to design a full-swing full adder cell with low number of transistors. The proposed full adder is implemented in MOSFET-like carbon nanotube technology and the layout is provided based on standard 32 nm technology from MOSIS. The simulation results using HSPICE show that there are substantial improvements in both power and performance of the proposed circuit compared to the latest designs. In addition, the proposed circuit has been implemented in conventional 32 nm process to compare the benefits of using MOSFET-like carbon nanotubes in arithmetic circuits over conventional CMOS technology. The proposed circuit can be applied in very high performance and ultra-low-power applications.

Static and dynamic characterization of robust superhydrophobic surfaces built from nano-flowers on silicon micro-post arrays

Superhydrophobic nano-flower surfaces were fabricated using MEMS technology and microwave plasma-enhanced chemical vapor deposition (MPCVD) of carbon nanotubes on silicon micro-post array surfaces. The nano-flower structures can be readily formed within 1–2 min on the micro-post arrays with the spacing ranging from 25 to 30 µm. The petals of the nano-flowers consisted of clusters of multi-wall carbon nanotubes. Patterned nano-flower structures were characterized using various microscopy techniques. After MPCVD, the apparent contact angle (160 ± 0.2°), abbreviated as ACA (defined as the measured angle between the apparent solid surface and the tangent to the liquid–fluid interface), of the nano-flower surfaces increased by 139% compared with that of the silicon micro-post arrays. The measured ACA of the nano-flower surface is consistent with the predicted ACA from a modified Cassie–Baxter equation. A high-speed CCD camera was used to study droplet impact dynamics on various micro/nanostructured surfaces. Both static testing (ACA and sliding angle) and droplet impact dynamics demonstrated that, among seven different micro/nanostructured surfaces, the nano-flower surfaces are the most robust superhydrophobic surfaces.

A low-voltage and energy-efficient full adder cell based on carbon nanotube technology

Abstract Scaling problems and limitations of conventional silicon transistors have led the designers to exploit novel nano-technologies. One of the most promising and feasible nano-technologies is CNT (Carbon Nanotube) based transistors. In this paper, a high-speed and energy-efficient CNFET (Carbon Nanotube Field Effect Transistor) based Full Adder cell is proposed for nanotechnology. This design is simulated in various supply voltages, frequencies and load capacitors using HSPICE circuit simulator. Significant improvement is achieved in terms of speed and PDP (Power-Delay-Product) in comparison with other classical and state-of-the-art CMOS and CNFET-based designs, existing in the literature. The proposed Full Adder can also drive large load capacitance and works properly in low supply voltages.

Chemical Vapor Deposition of Carbon Nanotubes: A Review on Growth Mechanism and Mass Production

This review article deals with the growth mechanism and mass production of carbon nanotubes (CNTs) by chemical vapor deposition (CVD). Different aspects of CNT synthesis and growth mechanism are reviewed in the light of latest progresses and understandings in the field. Materials aspects such as the roles of hydrocarbon, catalyst and catalyst support are discussed. Many new catalysts and new carbon sources are described. Growth-control aspects such as the effects of temperature, vapor pressure and catalyst concentration on CNT diameter distribution and single- or multi-wall formation are explained. Latest reports of metal-catalyst-free CNT growth are considered. The mass-production aspect is discussed from the perspective of a sustainable CNT technology. Existing problems and challenges of the process are addressed with future directions.

Multi-beam X-ray source breast tomosynthesis reconstruction with different algorithms.

Digital breast tomosynthesis is a new technique to improve the early detection of breast cancer by providing three-dimensional reconstruction volume of the object with limited-angle projection images. This paper investigated the image reconstruction with a standard biopsy training breast phantom using a novel multi-beam X-ray sources breast tomosynthesis system. Carbon nanotube technology based X-ray tubes were lined up along a parallel-imaging geometry to decrease the motion blur. Five representative reconstruction algorithms, including back projection (BP), filtered back projection (FBP), matrix inversion tomosynthesis (MITS), maximum likelihood expectation maximization (MLEM) and simultaneous algebraic reconstruction technique (SART), were investigated to evaluate the image reconstruction of the tomosynthesis system. Reconstructed images of the masses and micro-calcification clusters embedded in the phantom were studied. The evaluated multi-beam X-ray breast tomosynthesis system is able to generate three-dimensional information of the breast phantom with clearly-identified regions of the masses and calcifications. Future study will be done soon to further improve the imaging parameters' measurement and reconstruction.

LLNL licenses carbon nano-tube technology for desalination to Porifera

LLNL licenses carbon nano-tube technology for desalination to Porifera

ELISA-LOC: lab-on-a-chip for enzyme-linked immunodetection

A miniature 96 sample ELISA-lab-on-a-chip (ELISA-LOC) was designed, fabricated, and tested for immunological detection of Staphylococcal Enterotoxin B (SEB). The chip integrates a simple microfluidics system into a miniature ninety-six sample plate, allowing the user to carry out an immunological assay without a laboratory. Assay reagents are delivered into the assay plate without the need for separate devices commonly used in immunoassays. The ELISA-LOC was constructed using Laminated Object Manufacturing (LOM) technology to assemble six layers with an acrylic (poly(methyl methacrylate) (PMMA)) core and five polycarbonate layers micromachined by a CO(2) laser. The ELISA-LOC has three main functional elements: reagent loading fluidics, assay and detection wells, and reagent removal fluidics, a simple "surface tension" valve used to control the flow. To enhance assay sensitivity and to perform the assay without a lab, ELISA-LOC detection combines several biosensing elements: (1) carbon nanotube (CNT) technology to enhance primary antibody immobilization, (2) sensitive ECL (electrochemiluminescence) detection, and (3) a charge-coupled device (CCD) detector for measuring the light signal generated by ECL. Using a sandwich ELISA assay, the system detected SEB at concentrations as low as 0.1 ng ml(-1), which is similar to the reported sensitivity of conventional ELISA. The fluidics system can be operated by a syringe and does not require power for operation. This simple point-of-care (POC) system is useful for carrying out various immunological assays and other complex medical assays without a laboratory.

Lab-on-a-chip for carbon nanotubes based immunoassay detection of Staphylococcal Enterotoxin B (SEB)

We describe a new eight channel Lab-On-a-Chip (LOC) for a Carbon Nanotube (CNT) based immunoassay with optical detection of Staphylococcal Enterotoxin B (SEB) for food safety applications. In this work, we combined four biosensing elements: (1) CNT technology for primary antibody immobilization, (2) Enhanced Chemiluminescence (ECL) for light signal generation, (3) a cooled charge-coupled device (CCD) for detection and (4) polymer lamination technology for developing a point of care immunological assay for SEB detection. Our concept for developing versatile LOCs, which can be used for many different applications, is to use a modular design with interchangeable recognition elements (e.g. various antibodies) to determine the specificity. Polymer lamination technology was used for the fabrication of a six layer, syringe operated LOC capable of analyzing eight samples simultaneously. An anti-SEB antibody-nanotube mixture was immobilized onto a polycarbonate strip, to serve as an interchangeable ligand surface that was then bonded onto the LOC. SEB samples are loaded into the device and detected by an ELISA assay using Horse Radish Peroxidase (HRP) conjugated anti-SEB IgG as a secondary antibody and ECL, with detection by a previously described portable cooled CCD detector. Eight samples of SEB in buffer or soy milk were assayed simultaneously with a limit of detection of 0.1 ng mL(-1). CNT immobilization of the antibody increased the sensitivity of detection six fold. Use of a simple interchangeable immunological surface allows this LOC to be adapted to any immunoassay by simply replacing the ligand surface. A syringe was used to move fluids for this assay so no power is needed to operate the device. Our versatile portable point-of-care CCD detector combined with the LOC immunoassay method described here can be used to reduce the exposure of users to toxins and other biohazards when working outside the lab, as well as to simplify and increase sensitivity for many other types of immunological diagnostics and detection assays.

CARBonCHIP: Carbon Nanotubes Technology on Silicon Integrated Circuits; Some Key Results

CARBonCHIP ("Carbon Nanotubes Technology on Silicon Integrated Circuits") has been a three year EU FP6 STReP collaborative project aimed to determine whether carbon nanotubes are a viable material to be used in the manufacture of interconnected transistors for future electronic devices beyond the 22 nm node. The research activities performed within the CARBonCHIP consortium primarily focused on the back end of line leading to the ability to now selectively grow dense bundles of vertical CNTs (10E12 CNTs cm-2) inside small diameter vias (140 nm) with repeatable yield. The final project deliverable, summarised in this paper, has been the generation of a materials based roadmap indicating further development of CNTs as a viable building block in nanoelectronics IC devices to extend Moore's Law beyond the year 2020. As this is a public report, only information which has been published or disseminated at a public level is being documented.

CARBonCHIP: Carbon Nanotubes Technology on Silicon Integrated Circuits; Some Key Results

not Available.

WE-C-303A-01: Stationary-Gantry Tomosynthesis System for On-Line Image Guidance in Radiation Therapy Based On a 52-Source Cold Cathode X-Ray Tube

We present the design and simulation of an imaging system that employs a compact multiple source x-ray tube to produce a tomosynthesis image from a set of projections obtained at a single tube position. The electron sources within the tube are realized using cold cathode carbon nanotube technology. The primary intended application is tomosynthesis-based 3D image guidance during external beam radiation therapy. The tube, which is attached to the gantry of a medical linear accelerator (linac) immediately below the multileaf collimator, operates within the voltage range of 80-160 kVp and contains a total of 52 sources that are arranged in a rectilinear array. This configuration allows for the acquisition of tomographic projections from multiple angles without any need to rotate the linac gantry. The x-ray images are captured by the same amorphous silicon flat panel detector employed for portal imaging on contemportary linacs. The field-of-view (FOV) of the system corresponds to that part of the volume that is sampled by rays from all sources. The present tube and detector configuration provides an 8 cm×8 cm FOV in the plane of the linac isocenter when the 40.96 cm×40.96 cm imaging detector is placed 40 cm from the isocenter. Since this tomosynthesis application utilizes the extremities of the detector to record image detail relating to structures near the isocenter, simultaneous treatment and imaging is possible for most clinical cases, where the treated target is a small region close to the linac isocenter. The tomosynthesis images are reconstructed using the simultaneous iterative reconstruction technique (SART), which is accelerated using a graphics processing unit (GPU). We present details of the system design as well as simulated performance of the imaging system based on reprojections of patient CT images.

Carbon nanotubes terminated with hard magnetic FePt nanomagnets

The advancement in carbon nanotube (CNT) technology includes significant interest in their functionalization to modify their chemical and physical properties. In particular, the selective functionalization of the CNT ends opens exciting opportunities to design nanoscale architectures and networks. The realization of hard-magnetically terminated CNT via plasma enhanced chemical vapor deposition from Fe–Pt thin films is reported. Although FePt is rarely used as a catalyst for CNT synthesis the said binary catalyst affords attractive hard magnetic properties when present in the chemically ordered L10 phase.