bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cobalt Silicidation on Sub 100nm Hole Patterned Vertical Diode Formed by Silicon Epitaxial Growth and Its Electrical Properties
Authors: Lee Min Yong , Lee K. B. , Lee H. S. , Chae S. J. , Han I. K. , Kang H. S. , Park S. W. 
Published: April 2011

ABSTRACTSelf-aligned Cobalt silicide as ohmic contact layer on sub 100 nm hole patterned Si vertical diode formed by silicon epitaxial growth (SEG) is investigated and silicon epitaxial growth of higher than 4000 Å thickness and good crystalinity for PN diode has been successfully developed. Also, electrical isolation of 100 nm pitch size between diode and diode, and removal of unreacted Co/Ti/TiN layer have been realized by dip-out process without CMP simultaneously. Through the mechanism of void formation due to the variation of Si consumption rate during silicidation at limited hole pattern dimension, critical Co and Capping Ti thickness are investigated as various hole dimensions (80∼120 nm), and then with p+ type dopant species (49BF2, 11B). The ratio of Co thickness to hole dimension demonstrates void free cobalt silcidation on various pattern sizes of silicon epitaxial growth. Silicon epitaxial growing PN diodes including void free CoSi2 show excellent electrical performance, especially lower than 10 pA reverse off leakage current.
Structure and Electrical Properties of Atomic-scale In-Bi Nanowire Arrays
Authors: Owen James Hugh Gervase , Kubo Osamu , Bowler David 
Published: April 2011

ABSTRACTThe 1-nm-wide Bi nanoline has been proposed as a possible template for the growth of very-high-density arrays of atomic-scale nanowires, grown epitaxially on the technologically important Si(001) surface. Indium reacts with the Bi dimers, forming a unique zigzag atomic chain structure. Simulations of the appearance in STM of the lowest-energy isomer of this structure match experimental filled-states images. Calculation of the LDOS for the single-layer islands, finds that the nanowires are semiconducting, with a band gap smaller than that of the substrate, in good agreement with STS. A delocalised LUMO state is created, which may provide a conduction pathway along the nanowire. We have performed dual-probe STM conduction measurements along the In-Bi nanowires to test this prediction.
Infrared behavior of aluminum nanostructure sculptured thin films
Authors: Hofmann Tino , Schubert M. , Schmidt D. , Schubert E. 
Published: April 2011

ABSTRACTWe report on fabrication, structural and infrared optical characterization of nanostructure aluminum sculptured thin films prepared by glancing angle deposition (GLAD) and controlled substrate motion on p-type silicon. We discuss two structures, one with plate-like and one with screw-like (chiral) morphology. While the plate-like sample possesses a metal Drude behavior in the infrared spectral range, the chiral nanowire sample behaves non-metallic and reveals a series of intriguing resonances, which are equally spaced in frequency by ∼7.5 THz. We suggest that formation of 3D nano resonator circuits consisting of inductances and capacitances has occurred within the screw-like conductive aluminum wire sample, which might be responsible for the observed resonances. We suggest conductive GLAD nanostructures in combination with Schottky diodes to facilitate active or passive THz detector and transmitter devices.
Indium-assisted Growth of Si Nanowires: Perspectives on Controlled Growth for CMOS Applications
Authors: Iacopi Francesca , Eichhammer Yann , Massy Claire , Vereecken Philippe M , Moelans Nele , Richard Olivier , Smeets Dries , Blanpain Bart , De Gendt Stefan , Heyns Marc 
Published: April 2011

ABSTRACTSemiconductor nanowires are attractive nano- building blocks for microelectronics. However, the requirements for their manufacturing and application in the microelectronics industry are very demanding. Beyond compatibility with Si technology, full control on the characteristics of the grown wires (diameter, location, crystallinity, etc..), homogeneity on wafer –scale and reproducibility are essential. In this study we review critically important challenges for a controlled process of In –mediated growth of Si nanowires. First, we stress the importance of surface type for both particle catalysts and growth substrates. Both selection and preparation of such surfaces have large impact on growth, as they influence the initiation and the driving forces for the VLS growth mechanism. Moreover, wire characteristics such as morphology, crystalline quality and growth orientation appear more difficult to control when growing from particles with sizes below 40-50nm. This limitation arises as a result of both fundamental mechanisms and more specific constrains linked to the In-Si system.A few perspectives are given for the achievement of a controlled Si nanowire growth in a Si –technology compatible fashion.
Raman Spectroscopic Analysis of p-doped Bridged InP Nanowire
Authors: Sarkar Ataur , Islam M. Saif , Yi Sungsoo , Talin A. Alec 
Published: April 2011

ABSTRACTRaman spectroscopy was performed on magnesium (Mg) doped InP nanowires bridged between single crystal vertical silicon electrodes using a green laser (λ∼ 532 nm). First order TO-phonon and LO phonon-plasmon peaks observed at 305 cm−1 and 345 cm−1, respectively, are consistent with those for bulk single crystal InP. Misorientation of the nanowires is found to influence the TO and LO peak intensities. Bottom broadening up to ∼20 cm−1 of the TO peak due to the energy dispersion in the shifted Stokes spectrum is observed in long (∼6 μm) nanowires. Raman measurements indicated a trace of uncatalyzed InP on the insulating silicon oxide substrate and was verified through the electrical measurements of leakage currents before and after the nanowire growth. Initial investigation reveals that Raman spectroscopy can be a very useful in the study of nanowire heterostructures.
Preparation and Characterization of BN Nanotubes with Controllable Sizes by Template-aided Synthesis
Authors: Wang Yuting , Shimada Shiro , Kiyono Hajime , Yamamoto Yasunori 
Published: April 2011

ABSTRACTIn this study, an efficient approach to prepare high quality BN nanotubes (BNNTs) was developed. BNNTs with specific sizes were prepared by sublimation of ammonia borane complex (BH3NH3) using two kinds of porous alumina anodic membrane template in two independently temperature controlled furnaces in a glovebox filled with N2. The BNNTs with template were nitrided at different temperatures 1300 ∼ 1700 °C in NH3. The BNNTs of 200 – 300 nm wide°60×°m long, and 70 – 80 nm wide°×40 μm long were finally collected after removal of the template by etching of with 40 wt% NaOH solution. The fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of BN from BH3NH3. Ordered arrays of BNNTs were observed by scanning electron microscopy (SEM), and the microstructure of these BNNTs was investigated by transmission electron microscopy (TEM). It was found that the diameters of the BNNTs can be easily controlled by using templates with different pore sizes. The wall thickness of the nanotubes was increased by increasing the sublimation time or the amount of the starting BH3NH3. The crystallinity of BNNTs was improved at higher temperatures (1700 °C) in NH3.
Synthesis and Electronic Properties SWCNT Sheets
Authors: Lashmore David , White Brian , Schauer Mark , Mann Jenn 
Published: April 2011

ABSTRACTThe commercial synthesis of carbon nanotube sheets will be described. This process involves the following steps: chemical vapor deposition of long CNTs from mixed hydrocarbon type fuels, creation and stabilization of the catalyst, and a large textile forming device. Movies of the growth process will be presented and described. Further the electronic properties of these textiles will be presented and discussed as: (1) A function of temperature from −4 °K to 500 °C, (2) A function frequency from 0 up to about 30 GHz and (3) In a magnetic field up to 1000 Oe. It is shown that these yarns have semiconductor properties but surprisingly exhibit apparent metallic like conduction high at high frequencies. The thermoelectric behavior of the textiles (and yarns) made of this material will be discussed as will the applications in secondary batteries. A power level of up to three watts per gram for the thermoelectric material has been demonstrated.
Ab Initio Modeling of Contact Structure Formation of Carbon Nanotubes and Its Effect on Electron Transport
Authors: Luo Weiqi , Ravichandran Karthik , Windl Wolfgang , Fonseca Leonardo R.C. 
Published: April 2011

AbstractCarbon nanotube (CNT) devices are studied as a possible alternative to the current silicon based CMOS technology. The contacts between CNTs and metal electrodes in such devices exert great influence on the device performance. In this study, ab-initio temperature accelerated dy-namics are performed to study the contact formation between CNTs and Ti electrodes. Results indicate that CNTs undergo significant structural deformation, resulting in a significant decrease of the device conductance. This finding may explain the discrepancy between experimental and simulated results in molecular devices. However, more effects may need to be taken into account as we discuss for the example of the size effect of CNTs.
Chemoselective Polymers, Nanoparticles, and Nanotubes in Chemical Sensor and Preconcentrator Applications
Authors: Simonson Duane L , McGill R Andrew , Papantonakis Michael R. , Higgins Bernadette A. , Stepnowski Jennifer L. 
Published: April 2011

AbstractThe functionalization of polymers and nano-materials with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) groups provides materials suitable for a variety of preconcentrator and sensor applications. These are especially useful in high vapor pressure, hydrogen-bond basic vapor collection. These specific interactions lead to high efficiency collection of basic analytes such as DMMP (organophosphonates), DNT, and TNT (nitroaromatics). The lower vapor pressure analytes such as RDX have a larger dependence on surface interactions without specific (hydrogen bond) interactions. The use of carbosilane polymers with HFIP pendant groups offers dramatic improvements over fluoropolyol (FPOL) and siloxane polymers in sensor and precon applications. The sorbent capacity and thermal stability are both dramatically improved. In this work we will demonstrate the use of Carbon Nanotube (CNT) composites with HFIP polymers as sorbent coatings and evaluate their use as SPME coatings.
Nanoprober-Based Pick-and-Place Process for Site-Specific Characterization of Individual Carbon Nanotubes
Authors: Hantschel Thomas , Ryan Peter , Palanne Saku , Richard Oliver , Arstila Kai , Verhulst Anne S. , Bender Hugo , Ke Xiaoxing , Vandervorst Wilfried 
Published: April 2011

AbstractThe potential use of carbon nanotubes (CNT) as interconnects requires also new characterization approaches as the existing ones are optimized for three-dimensional materials and do not work for inherently one-dimensional structures like CNTs. Therefore, we have developed a so-called pick-and-place process which allows to remove an individual CNT from a specific site and to place it at another location for further analysis. The approach is based on nanomanipulation combined with scanning electron microscopy (SEM). This paper presents the pick-and-place concept and explains the different steps required for its successful application. We further demonstrate its power by characterizing individual CNTs using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The developed pick-and-place approach overcomes the challenge of site-specific analysis of CNT interconnects and strongly facilitates the routine analysis of CNTs.
Low-power and Fast-switching Organic Field-effect Transistors with Ionic Liquids
Authors: Ono S. , Seki S. , Hirahara R. , Tominari Y. , Takeya J. 
Published: April 2011

ABSTRACTWe report high-mobility rubrene single-crystal field-effect transistors with ionic-liquid electrolytes used for gate dielectric layers. As the result of fast ionic diffusion to form electric double layers, their capacitances remain more than 10 μF/cm2 even at 0.1 MHz. With high carrier mobility of 1.2 cm2/Vs in the rubrene crystal, pronounced current amplification is achieved at the gate voltage of only 0.2 V, which is two orders of magnitude smaller than that necessary for organic thin-film transistors with dielectric gate insulators. The results demonstrate that the ionic-liquid/organic semiconductor interfaces are suited to realize low-power and fast-switching field-effect transistors without sacrificing carrier mobility in forming the solid/liquid interfaces.
Numerical Modeling of Electrothermal Effects in Silicon Nanowires
Authors: Boztug Cicek , Bakan Gokhan , Akbulut Mustafa , Gokirmak Ali , Silva Helena 
Published: April 2011

AbstractAsymmetric melting was observed in electrically pulsed n-type (phosphorus) nanocrystalline silicon (nc-Si) wires fabricated lithographically. Scanning electron microscope (SEM) images taken from the pulsed wires showed that melting initiates from the ground terminal end of the wires instead of the center as initially expected. Asymmetry in the temperature profile is caused by heat exchanged between charge carriers and phonons when an electrical current is passed along a temperature gradient. This effect is known as Thomson effect, a thermoelectric heat transfer mechanism. One dimensional (1D) time dependent heat diffusion equation including Thomson heat term was solved to model the temperature profile on our structures. The modeling results show that Thomson effect introduces significant shifts in the temperature distribution. The effect of Thomson heat is modeled for various electrical pulse conditions and wires dimensions. Our results indicate that Thomson effect is significant in small scale electronic devices operating under high current densities.
Nano-scale Tribological Behavior of Polycrystalline Silicon Structural Films in Ambient Air
Authors: Alsem Daan Hein , van der Hulst Ruben , Stach Eric A. , Dugger Michael T. , de Hosson Jeff Th. M. , Ritchie Robert O. 
Published: April 2011

ABSTRACTDynamic friction, wear volumes and wear morphology have been studied for sliding wear in polysilicon in ambient air at μN normal loads using on-chip micron-scale test specimens. With increasing number of wear cycles, the friction coefficients show two distinct types of behavior: (i) an increase by a factor of two and a half to a steady-state regime after peaking at three times the initial value of about 0.10 ± 0.04, with no failure after millions of cycles; (ii) an increase by a factor larger than three followed by failure after ∼105 cycles. Additionally, the average nano-scale wear coefficient sharply increased in the first ∼105 cycles up to about 10−4 and then decayed by an order of magnitude over the course of several million cycles. For both modes of behavior, abrasive wear is the governing mechanism, the difference being attributed to variations in the local surface morphology (and wear debris) between the sliding surfaces. The oxidation of worn polysilicon surfaces only affects the friction coefficient after periods of inactivity (>30 min).
Detection of Organophosphate Gases and Biological Molecules using Embedded Piezoresistive Microcantilever Sensors
Authors: Porter Tim L , Vail Tim , Venedam Richard J 
Published: April 2011

AbstractEmbedded piezoresistive microcantilever (EPM) sensors have been used in the detection of a variety of analyte species. EPM sensors utilize a tiny piezoresistive microcantilever partially embedded into a sensing material to produce a sensing element that is compact, simple, resistant to movement and shock, and suitable for remote sensing applications. In the current project, we have used sensing materials comprised of an immobilizing polymer functionalized with either target enzymes or antibodies to detect two biological agents, Bacillus subtilis and Diisopropyl fluorophosphate (DFP). DFP is used as a simulant for organophosphate nerve agents, while BG is a large bacterial spore used as a simulant for other bacterial spores such as bacillus anthracis. Sensing results are presented for both types of EPM sensors.
Nanomechanics of Self-Assembled Monolayers on Nanoscale Gold Films
Authors: Aponte-Roman Milca I , Mann Adrian B 
Published: April 2011

AbstractSelf-assembled monolayers (SAMs) are thin organic films formed by a single layer of molecules adsorbed on a substrate. Since their discovery the preparation of these molecular assemblies has attracted the attention of interfacial researchers interested in controlled wetting of surfaces, adhesion, friction, chemical sensing, and high resolution lithography. However, little effort has gone into understanding how this nano-layer affects the mechanics of the underlying surface. In this study the nanomechanics of alkanethiolate SAMs on Au (111) films has been investigated using nanoindentation techniques. The research is aimed at establishing the effect of a SAM on the measured mechanical properties of the Au film. The SAMs considered for this study were made from 1-decanethiol, 96% (CH3(CH2)9-SH). Nanoindentation experiments were performed using a Triboindenter (Hysitron Inc., MN) using displacement control mode. Comparisons were made between the mechanical behavior of the Au films, the Au films plus SAMs and the glass substrate. A range of maximum indentation displacements were used. During the nanoindentation tests the load-displacement curves and the apparent mechanical properties were found to depend on the presence of the SAM film. Surprisingly, the effects of the SAM layer are seen even when the nanoindentation displacement is orders of magnitude greater that the SAM thickness. Many of the effects of the SAM can be explained by changes in the contact geometry and the ability of the SAM to sustain compressive loads when it is in a confined volume. The results and conclusions are potentially relevant to all thin adsorbed organic films, including protein layers on biomaterial surfaces and lubricants on engineering components.
Modeling of Dislocations and Mismatched Layers in Pentagonal Nanorods
Authors: Romanov Alexei L. , Romanov Alexei E. 
Published: April 2011

AbstractPentagonal nanorods (PNRs) are crystalline objects with unique fivefold symmetry. They are often experimentally observed for materials with FCC crystal structure. In an ideal case a PNR consists of five elastically distorted but otherwise perfect crystalline regions divided by low-energy twin boundaries. The elastic distortions in PNRs and associated stored elastic energy are effectively described in the framework of a disclination approach. As a result of mechanical stress relaxation, the stored energy can be diminished in expense of structural defect formation in PRN interior. It is demonstrated that a perfect multiple twinned PNR structure is unstable with respect to dislocation formation, i.e. prismatic dislocation loop or straight edge dislocation, for PNRs above a certain critical diameter. A new mechanism for the relaxation processes in PNRs is theoretically investigated. This mechanism assumes the formation of the shell possessing crystal lattice mismatch with respect to the PNR core region. The optimal magnitude for core/shell crystal lattice mismatch and optimal shell thickness providing maximum energy release for this mechanism of mechanical stress relaxation, are predicted.
Mechanical Properties of Evaporated Gold Films. Hard Substrate Effect Correction
Authors: Du Ke , Pang Xiaolu , Chen Chi , Volinsky Alex A. 
Published: April 2011

AbstractNanoindentation tests using the Berkovich indenter tip were performed on 50 and 200 nm thick polycrystalline gold films deposited on hard substrates. Gold film hardness increased with the indentation depth due to the influence of the substrate. A procedure based on the Joslin-Oliver method was introduced to correct for the substrate effect. The method utilizes the fact that the measured elastic modulus does not change significantly with the indentation depth, which allows reducing the contact area variation used in the hardness calculation.
Shape deformation of colloidal titania nanoparticles by means of ion irradiation
Authors: Cheang-Wong Juan-Carlos , Díaz-Fonseca Ana-Lilia 
Published: April 2011

AbstractSpherical submicrometer-sized titanium dioxide (TiO2 or titania) particles were prepared by the sol-gel method from hydrolysis and condensation of titanium butoxide Ti(OC4H9)4 using ammonia as a catalyst in ethanol/acetonitrile and annealing in air at 100°C. Subsequently, they were deposited onto silicon substrates, in order to form a monolayer of TiO2 particles. Then these samples were irradiated at room temperature with Si2+ ions at 4, 6 and 8 MeV, with fluences in the 2×1014-2×1015 Si/cm2 range, under an angle of 45° with respect to the sample surface. The titania particles were characterized by scanning electron microscopy to determine their size and shape before and after the ion irradiation. After the Si irradiation the spherical silica particles turned into ellipsoidal particles, as a result of the increase of the particle dimension perpendicular to the ion beam and the decrease in the direction parallel to the ion beam. This deformation effect increases monotonically with the ion fluence, and depends on the electronic energy loss of the impinging ion.
Plasma ion heating produces L10 FePt nanoclusters
Authors: Patterson Marlann Marinho , Rui Xiangxin , Li Xingzhong , Shield Jeff E. , Sellmyer David 
Published: April 2011

AbstractIn this study, cubic and spherical FePt clusters were created by inert gas condensation in an argon-helium dc sputter discharge under different flow and target power conditions. The plasma recipes for spherical and cubic clusters called for high He:Ar ratio, low target power and low He:Ar ratio, high target power, respectively. As expected, Langmuir probe measurements show the recipes led to larger ion density for the cubic case (2 × 108cm−3versus 6 × 106cm−3for spherical). We conclude that the larger density of argon ions increased the cluster-ion collision probability, heating the clusters in situ to promote atomic rearrangements and the formation of the orderedL10crystal structure rather than the disordered fcc structure.
Non-Hydrolytic Solution-Phase Synthesis of Anisotropic LiNbO3 and Nb2O5 Nanostructures
Authors: Wood Bryan D. , Gates Byron  D. 
Published: April 2011

AbstractThis paper describes an innovative and simple technique to synthesize anisotropic nanostructures of both lithium niobate (LiNbO3) and niobium oxide (Nb2O5). These materials were obtained using a solution-phase non-hydrolytic decomposition of LiNb(OPri)6 with or without the presence of Nb and Li-chlorides. The stability of LiCl is suggested as an explanation for the lack of LiNbO3 production in the chloride-based reaction. After 2 and 24 hours of reaction crystalline products of Nb2O5 and LiNbO3 are obtained without further thermal treatment. The products of both reactions contained a mixture of spherical and rod-like morphologies. Larger crystals of LiNbO3 and Nb2O5 were predominantly found to be anisotropic with aspect ratios of 7:1 and 3:1, respectively. These structures are believed to result from the natural anisotropy of the unit cell for these materials and from the use of triphenylphosphine oxide (TPPO) as a coordinating solvent. Our solution-phase synthesis is easily scaled-up as a one-pot procedure that offers a promising route to controlling crystal size and morphology. Details of the composition and the growth of our LiNbO3 and Nb2O5 nanostructures will be discussed in addition to the details of our experimental procedure.