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Nanotechnology, IEEE Transactions on

Issue 1 • Date Jan. 2011

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  • Table of contents

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  • IEEE Transactions on Nanotechnology publication information

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  • Table of contents

    Page(s): 1 - 2
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  • Editorial [device concepts, architectural strategies, and interfacing methodologies for realizing nanoscale sensor systems]

    Page(s): 3 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    The papers in this special issue explore Device Concepts, Architectural Strategies, and Interfacing Methodologies for Realizing Nanoscale Sensor Systems. This is volume II of the special issue. Some of the papers are based in part on oral and poster presentations at the Nanoelectronic Devices for Defense and Security Conference, held in Fort Lauderdale, FL, from September 27-October 2, 2009. View full abstract»

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  • Differential Amplifier Sensor Architecture for Increased Sensor Selectivity

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (270 KB) |  | HTML iconHTML  

    The use of a differential amplifier sensor architecture has been investigated as a route to improved sensor selectivity. Carbon nanotube FETs (CNTFETs) are used as both the transistors in a differential amplifier as well as chemical-sensing elements. Chemical functionalization of the CNTFETs can result in selective sensing. However, functionalized sensors are still likely susceptible to many undesired nonselective sensing events. By functionalizing two FETs differently, one FET can be tailored to selectively sense the analyte, and the other can be used as a reference to compensate for a wide range of interfering signals when the two FET outputs are subtracted. In this way, many interfering events can be discriminated against to yield robust and selective sensing in complex and dynamic environments. Proof of concept experiments showing the utility of background subtraction in software (calculated differential amplifier output) and hardware (using a breadboarded differential amplifier) are shown. View full abstract»

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  • Design, Fabrication, and Characterization of Three-Dimensional Single-Walled Carbon Nanotube Assembly and Applications As Thermal Sensors

    Page(s): 13 - 20
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    We present the design, fabrication, and characterization of vertical assembly of 3-D single-walled carbon nanotubes (SWNTs) thermal sensors. Carbon nanotubes (CNT) were deposited utilizing dielectrophoretic (DEP) assembly technique with a 98.7% yield. The scanning electron micrograph images revealed that by adjusting the height of the 3-D microelectrodes and the overlap between them allows control over bundle size, number of bundles, and effective length of the sensing elements. The two-terminal resistance of the 3-D devices was reduced by 20% on average from their initial values after the thermal annealing process. The 3-D SWNT thermal sensors were next characterized and a higher temperature coefficient of resistance (TCR) was measured compared to the previously reported DEP aligned CNT-based thermal sensors. The TCR of the single-electrode thermal sensor ranged from -0.157%/°C to -0.232%/°C, whereas the TCR of the multielectrode sensor varied from -0.327%/°C to -0.778%/°C measured during the heating cycle. The thermal sensitivities of these 3-D devices were also measured during cooling where the obtained TCR was close to the values obtained during the heating cycle. View full abstract»

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  • Local-Wetting-Induced Deformation of Rolled-Up Si/Si-Ge Nanomembranes: A Potential Route for Remote Chemical Sensing

    Page(s): 21 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (323 KB) |  | HTML iconHTML  

    We fabricate curled 3-D objects from semiconductor nanomembranes consisting of single-crystal silicon, which is epitaxially grown on silicon-germanium-on-insulator substrates. The curling is caused by relaxing the strain induced by lattice mismatch between silicon (Si) and germanium (Ge). Depending on the lithographically patterned geometries and their orientation with respect to the crystallographic direction, different shapes of tubes can be realized. Particularly interesting are tubes that are not completely closed, or partially open, whose mechanical response is ultraelastic. We demonstrate that applying acetone on such tubes generates a surface stress imbalance between the Si and Si-Ge layers, resulting in detectable shape changes. This mechanism has potential applications in chemical sensing, where the deformable curled structures act as dynamic-aperture reflector antennas. Our simulation suggests the curvature changes induced in the presence of certain chemical, such as acetone, will lead to distinctive far-field radiation patterns in the terahertz (THz) range. View full abstract»

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  • Selective Detection of Chemical and Biological Toxins Using Gold-Nanoparticle-Based Two-Photon Scattering Assay

    Page(s): 26 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (694 KB) |  | HTML iconHTML  

    Possible terrorist threats on water supplies are causes for concern given the easy availability of numerous biological and chemical toxins that could be used by a terrorist organization. In this article, we report gold-nanoparticle-based two-photon light-scattering (TPS) assay, for the label-free detection of arsenic and Salmonella bacteria separately, with excellent detection limit and selectivity over other analytes. Our experimental results show that arsenic can be detected quickly and accurately without any tagging, in 100-ppt level with excellent discrimination against other heavy metals. We have demonstrated that our TPS assay is capable of measuring the amount of arsenic in Bangladesh, West Bengal, and Nevada well water as well as in Mississippi river water. We have also shown that gold-nanoparticle-based TPS assay are capable for label-free detection of Salmonella typhimurium (S. typhimurium) with excellent detection limit (103 bacteria/mL) and high selectivity over other pathogens. The mechanism of TPS assay working principle has been discussed. Our results demonstrate the potential for a broad application of nanotechnology in practical defense applications. View full abstract»

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  • Optoelectronic Signatures of DNA-Based Hybrid Nanostructures

    Page(s): 35 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1090 KB) |  | HTML iconHTML  

    This paper presents a characterization of the vibrational modes of nanostructure-DNA complexes immobilized on substrates, such as silver-coated microspheres and silver nanostructure array DNA strands end terminated with titanium dioxide (TiO2) nanoparticles are used to study UV-induced cleaving of DNA molecules functionalized with indirect-bandgap semiconductors. In addition, conventional DNA-based molecular beacons were designed and applied in the detection of DNA of selected organisms. Micro-Raman (μRaman) measurements of DNA in water have proven to be a major challenge because of: 1) weak DNA signatures in solution; 2) changes in structural conformations of the DNA; and 3) environmental effects, such as temperature and pH of the solution in which DNA is suspended. We have studied optoelectronic properties of nanostructure-DNA complexes immobilized on silver nanosphere substrates as well as on Ag-coated micro- and nanostructures. In this research, self-assembled monolayers of DNA formed on these substrates were studied using μRaman techniques. These Raman spectra were used to identify prominent vibrational modes of DNA, and to characterize DNA Raman spectra for both B-DNA with a right-handed double helix, and Z-DNA with a left-handed double helix (S. C. Ha, K. Lowenhaupt, A. Rich, Y. Kim, and K. Kim, “Crystal structure of a junction between B-DNA and Z-DNA reveals two extruded bases,” Nature, Vol. 437, pp. 1183-1186, 2005). These Raman-based studies of the conformational states of DNA employ pH-changing trivalent salts, methylation of cytosine bases, and alternating GC bases. Moreover, DNA strands terminated with titanium dioxide (TiO2) nanoparticles were observed to undergo cleaving upon UV illumination. View full abstract»

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  • Spectral and Electrical Nanoparticle-Based Molecular Detection of Bacillus Anthracis Using Copolymer Mass Amplification

    Page(s): 44 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (577 KB) |  | HTML iconHTML  

    Nanoparticle-based detection of microorganisms has gained attention in recent years because of the need for rapid detection in multiple readout formats for clinical, food safety, and defense applications. The 2001 anthrax attacks are one example, where rapid detection would have aided in cleanup and containment efforts, and significantly reduced economic costs. Current detection methods, such as antibody recognition, polymerase chain reaction, and bio-barcode assays (BCA) are limited by shelf life, cost, complexity, or detection times. BCAs are very sensitive, but once the amplified single-stranded (ssDNA) output is obtained, up to four additional hours of readout time are required. Previously, BCA detection was used to identify the pagA gene from Bacillus anthracis. In this paper, we describe a modification of the BCA reporter ssDNA for rapid readout. Two ssDNA molecules were designed to copolymerize, and then, continually hybridize into double-stranded DNA (dsDNA). The dsDNA was then detected using Pico Green dye, an intercalating fluorescent dye. Additionally, a semimetallic nanoparticle was conjugated to SYBR 101 dye for electrical reduction/oxidation readout. Copolymerization and dye detection provide rapid readout of ssDNA from BCA with potential for multiplexed detection through electrical readout. View full abstract»

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  • Large-Scale Fabrication of Ordered Silicon Nanotip Arrays Used for Gas Ionization in Ion Mobility Spectrometers

    Page(s): 50 - 52
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (402 KB) |  | HTML iconHTML  

    The 9/11 events have led to an increase in the request for sensors and sensor systems that can detect rapidly, efficiently, and at moderate cost trace explosives and a whole range of toxic substances at diverse control points, e.g., at airports and inside air conditioning systems in aircraft and public buildings. To date, the security screening instruments of choice are ion mobility spectrometers (IMS), which are basically time-of-flight mass spectrometers (Sielemann, 1999 and Stach, 1997). Such instruments allow for the detection of explosives, chemical warfare agents, and illicit drugs. Widespread adoption of the IMS technology in civilian security screening applications, for instance, at airports, has been hindered due to the fact that state-of-the-art spectrometers employ radioactive ion sources. We report on fabrication and measurements of large-scale-ordered silicon nanotip arrays, used to replace the radioactive source for IMS gas ionization. Surface ionization mechanisms on the platinum-coated silicon surface can be significantly increased compared to flat structures due to the strong field enhancement at the tips. We will show measurements of the ion current of planar surfaces compared to microstructured surfaces as well as a photoelectrochemical etching process that allows to etch flat tips with a low aspect ratio as well as long tips with high aspect ratios with exact control about the tip profile. View full abstract»

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  • Highly Reproducible Nanolithography by Dynamic Plough of an Atomic-Force Microscope Tip and Thermal-Annealing Treatment

    Page(s): 53 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (461 KB) |  | HTML iconHTML  

    An approach has been developed to use atomic-force microscope (AFM) to pattern materials at the nanoscale in a controlled manner. By introducing a thermal-annealing process above the glass-transition temperature of poly (methylmethacrylate) (PMMA), the profile of indented nanopatterns has been dramatically improved by abatement of the tip-induced debris. This eliminates the main problem of the previous AFM-based tip-ploughing lithography method, namely the debris formation during the nanoplough and trench refilling by debris. We are able to reproducibly fabricate nanopatterns down to 40 nm. Meanwhile, the AFM-tip lifetime has been increased substantially. In particular, the adhesion between the PMMA layer on the edge of trenches and the substrate is significantly improved to enable reliable pattern transfer into GaAs/AlGaAs heterostructures by wet-chemical etching. Functional nanodevices with a lateral feature size of 100 nm to an etching depth of 70 nm are demonstrated using the method. View full abstract»

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  • Surface Engineering of Graphene-Enzyme Nanocomposites for Miniaturized Biofuel Cell

    Page(s): 59 - 62
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB) |  | HTML iconHTML  

    A novel approach to the surface functionalization for membraneless enzymatic glucose/oxygen biofuel cell applications is described. The biofuel cell employs the gold plate electrodes modified by specific graphene-enzyme conjugations, which are immobilized by electrochemical deposition of the conducting polypyrrole polymer. The electrochemical activity of these electrodes is superior to the electrodes immobilized with sol-gel. Such enhancements can be attributed to the excellent electrical property and enzyme loading capability of the polypyrrole material. The power output and the biostability of the integrated biofuel cell are also improved. View full abstract»

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  • Fabrication of Zinc Oxide Nanotubes by Chemical Bath Deposition Using Ion Track-Etched Templates

    Page(s): 63 - 69
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    Nanotubes consisting of zinc oxide were fabricated by electroless deposition, using ion track-etched polycarbonate templates. To achieve nanotubes with thin walls and small surface roughness, the tubes were generated by a several steps containing procedure under aqueous conditions. The reported approach that is described shortly will process open-end nanotubes with well-defined outer diameter and wall thickness. View full abstract»

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  • Efficient Parallel Computation of Molecular Potential Energy Surfaces for the Study of Light-Induced Transition Dynamics in Multiple Coordinates

    Page(s): 70 - 74
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (933 KB) |  | HTML iconHTML  

    The conformational dynamics of molecules that arise due to light-induced transitions are critically important in many biochemical reactions, and therefore dictate the functionality of many types of biological sensors. Therefore, researchers of biological science and biological-inspired technology often need to prescribe the molecular geometry of the stable states and the associated transition trajectories that occur as a result of external excitation, e.g., light-induced transitions from the ground state to the excited states. The traditional approach to study this type of phenomenology is to limit the number of varying molecular coordinates to one or a few due to the considerable computational expense of the required physically modeling required for generating an accurate physical model for analysis. While the conformational dynamics for some types of simple molecules (e.g., retinal) are known to be adequately described by one or few numbers of molecular coordinates, light-induced transitions in arbitrarily complex molecules can be expected to involve the influence of multiple coordinates, and their influence can be expected to vary as a function of time. The research reported here will address the development of parallel computational algorithms that allow for the highly efficient study of molecular conformational dynamics over multiple numbers of multidimensional energy surfaces. Here, the goal is the development of a simulation tool that is capable of: constructing physically accurate multidimensional potential energy surfaces (i.e., from first-principle physical modeling codes); deriving the natural trajectories to local minima within individual surfaces; and that allows for dynamics human interfacing for specifying the transition between energy surfaces and the number of coordinates to be used for the optimization within a particular energy surface. As will be illustrated, this type of physics-based simulation tool will allow researchers to efficiently explore- - the light-induced conformation dynamics associated with complex biomolecules, and therefore, be a useful tool for the design of biological-sensing processes in the future. View full abstract»

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  • Modeling Pressure-Driven Transport of Proteins Through a Nanochannel

    Page(s): 75 - 82
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (501 KB) |  | HTML iconHTML  

    Reducing the size of a nanofluidic channel not only creates new opportunities for high-precision manipulation of biological macromolecules but also makes the performance of the entire nanofluidic system more susceptible to undesirable interactions between the transported biomolecules and the walls of the channel. In this paper, we report molecular dynamics simulations of pressure-driven flow through a silica nanochannel and characterize, with atomic resolution, adsorption of a model protein to the surface of the nanochannel. Although the simulated adsorption of the proteins was found to be nonspecific, it had a dramatic effect on the rate of the protein transport. To determine the relative strength of the protein-silica interactions in different adsorbed states, we simulated flow-induced desorption of the proteins from the silica surface. Our analysis of the protein conformations in the adsorbed states did not reveal any simple dependence of the adsorption strength on the size and composition of the protein-silica contact, suggesting that the heterogeneity of the silica surface may be an important factor. View full abstract»

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  • Edge Effect in Perfectly Conducting Periodic Subwavelength Structures

    Page(s): 83 - 87
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (273 KB) |  | HTML iconHTML  

    The subterahertz (THz) region of absorption spectra (2-30 cm-1) of biomolecules reveals low-frequency molecular motions as resonances that can serve as fingerprints specific to molecules. Nanoscale edge effect in subwavelength periodic slit arrays can be used to increase the coupling of incident THz radiation to the biological material under the test due to the local electric-field enhancement, thus improving detection sensitivity and special resolution of THz resonance vibrational spectroscopy. In this paper, propagation of polarized light through 1-D grating made of perfect conducting metallic slits is considered. The analytical integral equation is derived and numerical solution is found in a long wavelength limit. The simulation program is developed that permits to find transmission characteristics of periodic structures and distribution of electromagnetic (EM) field across the slit with the goal to optimize the structure geometry. The perfect conductor approximation gives us an upper estimate of achievable enhancement of electric field in this case. View full abstract»

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  • Spatial Mapping of the Dirac Point in Monolayer and Bilayer Graphene

    Page(s): 88 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (298 KB) |  | HTML iconHTML  

    We have mapped the Dirac point in exfoliated monolayer and bilayer graphene using spatially resolved scanning tunneling spectroscopy measurements at low temperature. The Dirac-point shifts in energy at different locations in graphene. However, a cross correlation with the topography shows no correlation indicating that topographic features, such as ripples are not the primary source of the variation. Rather, we attribute the shift of the Dirac point to random charged impurities located near the graphene. Our findings emphasize the need to advance exfoliated graphene sample preparation to minimize the effect of impurities. View full abstract»

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  • Observation of Space-Charge-Limited Transport in InAs Nanowires

    Page(s): 92 - 95
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    Recent theory and experiment have suggested that space-charge-limited (SCL) transport should be prevalent in high aspect ratio semiconducting nanowires (NWs). We report on InAs NWs exhibiting this mode of transport and utilize the underlying theory to determine the mobility and effective carrier concentration of individual NWs, both of which are found to be diameter dependent. Intentionally induced failure by Joule heating supports the notion of SCL transport and proposes reduced thermal conductivity due to the NWs' polymorphism. View full abstract»

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  • Room-Temperature Operation of Silicon Single-Electron Transistor Fabricated Using Optical Lithography

    Page(s): 96 - 98
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (183 KB) |  | HTML iconHTML  

    We report on room-temperature operation of Si nanowires (SiNWs) based single-electron transistors (SETs) fabricated based on the top-down approach using conventional optical lithography. The SETs exhibit strong Coulomb oscillation at room temperature due to extreme small size of SiNW, which has a diameter of 4 nm. The optical lithography approach is attractive compared to the commonly used electron beam lithography for the fabrication of SETs because it offers the possibility of integrating Si single-electron electronics with CMOS technology. View full abstract»

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  • Ultralow-Power Single-Wall Carbon Nanotube Interconnects for Subthreshold Circuits

    Page(s): 99 - 101
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (181 KB) |  | HTML iconHTML  

    Single-wall carbon nanotube (SWNT) interconnects, though seem promising, have fundamental and practical limitations. The resistance of individual SWNTs is quite large because of which dense SWNT bundles are needed. However, there has been little progress in wafer-level fabrication of horizontal bundles of densely packed nanotubes. This letter reports that individual SWNTs can be used as interconnects in subthreshold circuits to improve delay and energy-per-bit by up to 5 times and 6 times, respectively. In light of recent advances in wafer-level fabrication of long aligned isolated SWNTs, the presented results can potentially open up a new and less challenging path toward SWNT interconnects. View full abstract»

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  • Surface Amplification of L-Glutamate Using a Patterned Bienzymatic System for Biosensing Applications

    Page(s): 102 - 110
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    Electronic sensing of neurotransmitter molecules is based on a diffusion-limited process, which requires the immobilization of biological recognition elements as close as possible to the active area of the sensor. Moreover, in many applications, the analyte concentration is very low. In particular, the in situ detection of neurotransmitter release from neurons is challenging due to the limited number of molecules secreted and their fast diffusion and reuptake immediately after release. In this paper, we present a method that allows for the local amplification of L-glutamate directly on the chip surface. Our approach is based on the surface patterning of a bienzymatic system consisting of glutamate oxidase (GLOD) and glutamic-pyruvate transaminase (GPT) that amplifies L-glutamate via a recycling process. The surface chemistry was optimized for maximal enzyme loading. The level of amplification was determined using a colorimetric assay. Coimmobilization of GLOD and GPT yielded at least a doubling of the signal, and increasing the surface concentrations of each enzyme led to amplification levels that approached those obtained in solution. We show that these enzymes can be patterned on substrates using a flip chip bonder for aligned microcontact printing. Furthermore, primary mouse hippocampal neurons were successfully cultured on these patterned surfaces and remained viable for at least five days. The enzymatic pattern was preserved on the substrate surface for the same time period. Lastly, amplification of L-glutamate released from neurons seven days in vitro was detected. Thus, we conclude that this bienzymatic system can ultimately be applied to biosensor surfaces for the in vitro detection of L-glutamate. View full abstract»

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  • Equivalent-Circuit Modeling of Nonradiative Surface Plasmon Energy Transfer Along the Metallic Nanowire

    Page(s): 111 - 120
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    An analytical methodology for establishing an equivalent-circuit network of nonradiative surface plasmon (SP) energy transport along the metallic nanowire (MNW) is presented. To find out the passive elements for MNW, the SP dispersion and damping relation through modified Bessel function electromagnetic (EM) field expansion was derived, thus demonstrating the low-pas transmission-line (TL) model. Specifically, the low-pass TL parameters, such as series impedance (Z) and shunt admittance ( Y) can be calculated based on the lumped-element model and harmonic-voltage (current) distribution. Furthermore, the equivalent-circuit parameters, such as resistance (R), inductance (L), capacitance (C) and conductance (G), are obtained by employing the finite difference (FD) discretization method such as T-cell RLCG networks. These equivalent-circuit elements can be verified by the HSPICE circuit simulation and 3-D scattered finite-difference time-domain (FDTD) method. Finally, the parallel MNWs are modeled as equivalent-circuit networks by using the electrostatic coupling. View full abstract»

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  • Quantum Threshold Voltage Modeling of Short Channel Quad Gate Silicon Nanowire Transistor

    Page(s): 121 - 128
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (751 KB) |  | HTML iconHTML  

    In this paper, a physically based analytical quantum linear threshold voltage model for short channel quad gate MOSFETs is developed. The proposed model, which is suitable for circuit simulation, is based on the analytical solution of 3-D Poisson and 2-D Schrödinger equation. Proposed model is fully validated against the professional numerical device simulator for a wide range of device geometries and also used to analyze the effect of geometry variation on the threshold voltage. View full abstract»

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  • Annular Spin-Transfer Memory Element

    Page(s): 129 - 134
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (227 KB) |  | HTML iconHTML  

    An annular magnetic memory that uses a spin-polarized current to switch the magnetization direction or helicity of a magnetic region is proposed. The device has magnetic materials in the shape of a ring (1-5 nm in thickness, 20-250 nm in mean radius, and 8-100 nm in width), comprising a reference magnetic layer with a fixed magnetic helicity and a free magnetic layer with a changeable magnetic helicity. These are separated by a thin nonmagnetic layer. Information is written using a current flowing perpendicular to the layers, inducing a spin-transfer torque that alters the magnetic state of the free layer. The resistance, which depends on the magnetic state of the device, is used to read out the stored information. This device offers several important advantages compared with conventional spin-transfer magnetic random access memory devices. First, the ring geometry offers stable magnetization states, which are, nonetheless, easily altered with short current pulses. Second, the ring geometry naturally solves a major challenge of spin-transfer devices: writing requires relatively high currents and a low impedance circuit, whereas readout demands a larger impedance and magnetoresistance. The annular device accommodates these conflicting requirements by performing reading and writing operations at separate read and write contacts placed at different locations on the ring. View full abstract»

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Aims & Scope

The IEEE Transactions on Nanotechnology is devoted to the publication of manuscripts of archival value in the general area of nanotechnology, which is rapidly emerging as one of the fastest growing and most promising new technological developments for the next generation and beyond.

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Meet Our Editors

Editor-in-Chief
Kang L. Wang
University of California, Los Angeles
420 Westwood Plaza
Rm 66-147C, Engineering IV
Los Angeles, CA  90095-1594  90095-1594  USA
eic@tnano.org