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Nanotechnology, IEEE Transactions on

Issue 5 • Date Sept. 2009

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Displaying Results 1 - 21 of 21
  • Table of contents

    Page(s): C1
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  • IEEE Transactions on Nanotechnology publication information

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  • Table of contents

    Page(s): 561 - 562
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  • Editorial

    Page(s): 563 - 564
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  • Nanotube Boiler: Attogram Copper Evaporation Driven by Electric Current, Joule Heating, Charge, and Ionization

    Page(s): 565 - 568
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (381 KB) |  | HTML iconHTML  

    Controlled copper evaporation at attogram level from individual carbon nanotube (CNT) vessels, which we call nanotube boilers, is investigated experimentally and theoretically. We compared the evaporation modes induced by electric current, Joule heating, charge, and ionization in these CNT boilers, which can serve as sources for mass transport and deposition in nanofluidic systems. Experiments and molecular dynamics simulations show that the most effective method for evaporation is by positively ionizing the encapsulated copper; therefore, an electrostatic field can be used to guide the flow. View full abstract»

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  • Nanocrystal Photovoltaic Paint Sprayed With a Handheld Airbrush

    Page(s): 569 - 573
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (341 KB) |  | HTML iconHTML  

    A complete photovoltaic cell was fabricated using only a handheld airbrush, dilute solutions of CdSe and CdTe nanorods, commercially available silver paint, and transparent-conducting-electrode-coated glass. Produced and stored under ambient conditions, these fully functioning solar cells are stable for months. As a heterojunction cell, the migration of carriers within the CdTe and CdSe layers is polarity-dependent, which directly contributes to the photoinduced voltaic cell response observed. The suitability of a handheld airbrush to create high-quality films by varying solution concentration, air pressure, and nanorod surface functionalization was explored. Notably, ultrasmooth surfaces comparable to spin-coated quality films can be formed from 20 to 500 nm thickness, with continuous, uninterrupted optical domains such that strong light diffraction is observed. While current estimated efficiency is low (<0.01%), this method demonstrates the potential of solar cells that can be incorporated into a variety of devices of unconventional size or design. View full abstract»

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  • Fabrication and Characterization of Interconnected Nanowell Molecular Electronic Devices in Crossbar Architecture

    Page(s): 574 - 581
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (638 KB) |  | HTML iconHTML  

    The implementation of circuit architectures based on molecular electronic devices has been impeded by the availability of facile fabrication schemes for the interconnection of individual devices. The deposition and patterning of a top contact layer between adjoining devices for interconnection purposes can result in contacts of poor fidelity, which introduces artifacts in the I-V characteristics that are not attributable to molecular transport between the contacts. In this study, through the fabrication of interconnected devices within the crossbar device architecture, we demonstrate that the vapor-phase molecular deposition method for fabrication of device layers was compatible with the massively parallel microelectronic fabrication process of liftoff, for patterning of contact layers. A prepatterned device with Au bottom contacts, as well as a bilayer resist for patterning the top Au contacts through postdeposition liftoff was used as the substrate for vapor-phase deposition of a monolayer of conjugated oligo-(phenylene ethynylene) (plain-OPE) molecules and patterning of the top metal contact layer. Interconnection in series and parallel configurations was confirmed by I-V characteristics similar to classical resistors with equivalent conductivity of each individual molecular device. Additionally, to better understand molecular transport in the device junctions, we performed temperature-dependent I-V studies on individual molecular devices that were fabricated using prepatterned Au bottom contacts as the substrate for solution-phase deposition of the molecular monolayer, onto which the Au top contacts were evaporated and patterned using a shadow mask. Molecular layers of two distinctly different room-temperature I-V characteristics, including nonswitching plain-OPE and switching nitro-OPE molecular devices, were used to study the fidelity of the molecular junctions. Based on the persistence of the device characteristics of both types of molecular layers down to 10- - 0 K, and in particular, the observation of switching between "high" and "low" conductivity states at characteristic threshold voltages at all temperatures, only with nitro-OPE molecular devices, and not with plain-OPE molecular devices, we conclude that the observed transport was a characteristic molecular signature not dependent on filament formation at contacts. View full abstract»

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  • Coupled Dielectric Nanoparticles Manipulating Metamaterials Optical Characteristics

    Page(s): 582 - 594
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1442 KB) |  | HTML iconHTML  

    In this paper, we investigate the concept and theory of all-dielectric metapatterned structures that manipulate electric and magnetic optical characteristics. A 3-D array of dielectric particles is designed, where the spheres operate in their magnetic modes and their couplings offer electric modes. An analytical solution for the problem of plane wave scattering by 3-D array of dielectric nanospheres is presented. FW multipole expansion method is applied to express the optical fields in terms of the electric and magnetic dipole modes and the higher order moments. By enforcing the boundary conditions at the surface of each sphere, with the use of the translational addition theorem for vector spherical wave functions, required equations to determine the scattering coefficients are obtained. Novel materials features in optics are demonstrated. Electric and magnetic scattering coefficient resonances around the same frequency band are obtained. It is highlighted how a metapatterned structure constructed from dielectric nanosphere unit cells can provide electric and magnetic modes resulting in backward wave phenomenon. A comprehensive circuit model based on the RLC (resistor, inductor, and capacitor) realization is presented to successfully analyze the scattering performance of a dielectric nanosphere. To better understand the physics of an array of spheres, circuit models for the interactions, and couplings between spheres are also accomplished. The engineered dispersion diagram for a 3-D array of identical highly coupled nanospheres is scrutinized, verifying that the high couplings between spheres can offer the backward wave characteristics. View full abstract»

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  • A Gated Twin-Bit (GTB) Nonvolatile Memory Device and Its Fabrication Method

    Page(s): 595 - 602
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1237 KB) |  | HTML iconHTML  

    In this study, a nonvolatile memory (NVM) device of novel structure in three-dimension is introduced and validated. It is based on a pillar structure where two memory nodes commonly reside. The storage nodes are controlled by a single control gate so that spaces between silicon pillars can be reduced, in which additional gates called cutoff gates realize perfect operations. Gated twin-bit (GTB) NVM device is considered as the ultimate form of 3-D NVM device based on double-gate structure in a sense that the use of common gate makes maximal integration possible. The operation schemes and fabrication method of the GTB NVM device are also introduced. View full abstract»

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  • 3-D Nonequilibrium Green's Function Simulation of Nonperturbative Scattering From Discrete Dopants in the Source and Drain of a Silicon Nanowire Transistor

    Page(s): 603 - 610
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    As these As transistors are scaled to nanometer dimensions, the discreteness of the dopants becomes increasingly important. Transistors of 3 times 3 nm2 cross section contain, on average, approximately one dopant atom per nanometer of length, making any self-averaging impossible. The individual random dopants act as localized scatterers whose distribution, and therefore, impact on the electron transport, varies from device to device. This is complemented by electrostatic variation in the potential that controls the threshold voltage and the dominant current paths. The current density is greatly influenced by resonances associated with the attractive potential of the donors and screening effects. In this paper, for the first time, a full 3-D nonequilibrium Green's function (NEGF) simulation in the effective mass approximation has been used to study the influence of individual discrete donors in the source/drain on the I-V characteristics of a narrow n-channel Si nanowire transistor. We have compared devices with microscopically different configuration of dopants. The simulated variations in the I-V curves are analyzed with reference to the behavior of the transmission coefficients. We have highlighted the importance of resonance states when solving the NEGF and Poisson equations self-consistently. View full abstract»

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  • A Simple Method for Measuring Si-Fin Sidewall Roughness by AFM

    Page(s): 611 - 616
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (477 KB) |  | HTML iconHTML  

    The gate oxide reliability and the electrical behavior of FinFETs are directly related to the surface characteristics of the fin vertical sidewalls. The surface roughness of the fin sidewalls is one of the most important structural parameters to be monitored in order to optimize the fin patterning and postetch treatments. Because of the nanometer-scale dimensions of the fins and the vertical orientation of the sidewall surface, their roughness measurement is a serious challenge. In this paper, we describe a simple and effective method for measuring the sidewall morphology of silicon fins by conventional atomic force microscopy. The present methodology has been employed to analyze fins as etched by reactive ion etching and fins repaired by sacrificial oxidation. The results show that sacrificial oxidation not only reduces the roughness of the sidewalls, but also rounds the top corners of silicon fins. The present method can also be applied to characterize sidewall roughness of other nanostructures and materials such as the polysilicon gate of transistors or nanoelectromechanical beams. View full abstract»

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  • A New Closed-Form Solution to Light Scattering by Spherical Nanoshells

    Page(s): 617 - 626
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (702 KB) |  | HTML iconHTML  

    Light or electromagnetic wave scattered by a single sphere or a coated sphere has been considered as a classic Mie theory. There have been some further extensions that were made further based on the Mie theory. Recently, a closed-form analytical model of the scattering cross section of a single nanoshell has been considered. The present paper is documented further, based on the work in 2006 by Alam and Massoud, to derive another different closed-form solution to the problem of light scattered by the nanoshells using polynomials of up to order 6. Validation is made by comparing the present closed-form solution to the exact Mie scattering solution and also to the other closed-form solution by Alam and Massoud. This study is found to be, however, more generalized and also more accurate for the coated spheres of either tiny/small or medium sizes than that of Alam and Massoud. Therefore, the derived formulas can be used for accurately characterizing both surface plasmon resonances of nanoparticles (of small sizes) or nanoantenna near-field properties (of medium sizes comparable with half wavelength). View full abstract»

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  • Polymer-Based Flexible Schottky Diode Made With Pentacene–PEDOT:PSS

    Page(s): 627 - 630
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (401 KB) |  | HTML iconHTML  

    This paper reports a polymer-based flexible Schottky diode made on a flexible cellulose substrate with poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate)-pentacene (PEDOT:PSS). Pentacene was dissolved into the N-methylpyrrolidone (NMP) solvent and mixed with PEDOT:PSS. Three-layered Schottky diodes consisting of Al, PEDOT:PSS or pentacene-PEDOT:PSS, and Au were fabricated. The current density of Au/PEDOT:PSS/Al Schottky diode (4.8 muA/cm2 at 2.5 V/mum) was drastically improved to 440 muA/cm2 at 1.9 V/mum when the pentacene-PEDOT:PSS was used. This enhancement of current density of Schottky diode is promising for flexible electronic devices. View full abstract»

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  • Complete Logic Functionality of Reconfigurable RTD Circuit Elements

    Page(s): 631 - 642
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (615 KB) |  | HTML iconHTML  

    Innovative nanoscale devices have been developed to enhance future circuit design to overcome physical barriers hindering the CMOS technology. Among the emerging nanodevices, resonant tunneling diodes (RTDs) have demonstrated promising electronic features due to their high-speed switching capability and functional versatility. Great circuit functionality can be achieved through integrating heterostructure FETs (HFETs) in conjunction with RTDs to modulate effective negative differential resistance. In this paper, we propose novel programmable logic elements (PLEs) implemented in threshold gates (TGs) and multithreshold TGs by exploring RTD/HFET monostable-bistable transition logic element (MOBILE) principles. Our three-input PLE can be configured through five binary control bits to realize all the three-variable logic functions, which is, to the best of our knowledge, the first single RTD-based structure that provides complete Boolean logic implementation. It is also a more efficient reconfigurable circuit element than a general lookup table that requires eight configuration bits for three-variable functions. We further extend the design concept to construct a more versatile four-input PLE. A comprehensive comparison of three- and four-input PLEs provides an insightful view of design tradeoffs between performance and area. We present the mathematical proof of PLE's logic completeness based on Shannon expansion, as well as the HSPICE simulation results of the programmable and primitive RTD/HFET gates that we have designed. An efficient control bit generating algorithm is developed by using a special encoding scheme to implement any given logic function. Based on our PLE structures, we propose a reconfigurable architecture, namely MORE, which offers dynamic reconfigurability without incurring latency overheads, due to the intrinsic self-latching property of MOBILE circuits. An efficient reconfiguration data generation algorithm is also built to take full advantage of - - our MORE architecture. The experimental results indicate that it can help reduce the reconfiguration cost by 37% on average. View full abstract»

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  • A SPICE-Compatible New Silicon Nanowire Field-Effect Transistors (SNWFETs) Model

    Page(s): 643 - 649
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (589 KB) |  | HTML iconHTML  

    Extraction of carrier mobilities of silicon nanowire FETs (SNWFETs) with Schottky source and drain contacts is performed using a newly developed compact model, which is suitable for efficient circuit simulation. The SNWFET model is based on an equivalent circuit including a Schottky diode model for two metal-semiconductor contacts and a SPICE LEVEL 3 MOSFET model for an intrinsic NW. The Schottky diode model is based on our recently developed Schottky diode model that includes thermionic field emission for reverse bias and thermionic emission mechanism for forward bias. It also includes a new analytical Schottky barrier height model dependent on the gate voltages as well as the drain-source voltages. The results simulated from the SNWFET model reproduce various, previously reported experimental results within 10% errors. The mobilities extracted from our model are compared with the mobility calculated without considering the Schottky contacts. View full abstract»

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  • Electrical Characteristics of Hybrid Nanoparticle–Nanowire Devices

    Page(s): 650 - 653
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    Gold nanoparticles synthesized by a colloidal method were deposited in an Al2O3 dielectric layer of an omega-gated single ZnO nanowire FET. These gold nanoparticles were utilized as localized trap sites. The adsorption of the gold nanoparticles on an Al2O3-coated ZnO nanowire was confirmed by high-resolution transmission electron microscopy. In this study, a hybrid nanoparticle-nanowire device was fabricated by conventional Si processing. Its electrical characteristics indicated that electrons in the conduction band of the ZnO nanowire can be transported to the localized trap sites by gold nanoparticles for gate voltages greater than 1 V, through the 10-nm-thick Al 2O3 tunneling oxide layer. View full abstract»

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  • Characterization of Near-Interface Oxide Trap Density in Nitrided Oxides for Nanoscale MOSFET Applications

    Page(s): 654 - 658
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    This paper presents the depth profile of oxide trap density, extracted from the dual gate processed thermally grown oxide in NO ambient and remote plasma nitrided oxides by using multifrequency and multitemperature charge pumping technique in conjunction with the tunneling model of trapped charges. Nitrided oxide is widely used to improve the reliability of nanoscale MOSFETs because it can decrease the degradation of gate oxide due to the generation of traps therein. Based on the measurement, the optimum nitrogen concentration in such typical nitrided process is discussed in correlation with the gate oxide thickness for nanoscale CMOSFETs. View full abstract»

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  • IEEE Transactions on Nanotechnology information for authors

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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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Editor-in-Chief
Kang L. Wang
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