bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single Shot of Arf Laser-Induced Photochemical Nucleation of Copper on Polyethylene-Terephthalate Surface
Authors: Tokunaga H. , Murahara M. 
Published: April 2011

ABSTRACTCopper nuclei was grown on a PET surface in the copper sulfate water solution ambience with only one shot of ArF laser.· General electronic circuit printed boards have been made by sticking the copper foils with adhesive agents after having made the foil surface rough. Consequently, even the printed board of low conductivity might generate a high frequency noise due to the difference between the copper foils and adhesive agents. If atoms composing plastics and metal could be combined by a chemical method instead of the conventional physical methods, a hybrid material made of both plastics and metal would be produced.We have reported for the substitution of copper atoms on an all-aromatic-polyimide surface by a single shot of ArF laser irradiation In this study, with one single shot of ArF laser, we succeeded in growing the Cu nuclei on the PET film whose ultraviolet absorption is lower than all-aromatic-polyimide. The sample surface was photo-oxidized with the Xe2 excimer lamp in pre-treatment. A fused silica glass was placed on the sample surface, and the sulfate water solution was poured into the gap between the glass and the sample to form a thin liquid layer. Then, the sample was vertically irradiated once by the circuit patterned ArF laser light with the laser fluence of 28mJ/cm2. The photo-dissociated copper atom formed the C-O-Cu bond with active oxygen to sub stitute on the PET surface. The modified sample was, then, immersed in the electro less plating solution at 60 degrees Celsius for 15 minutes; the copper thin film of about 24mm was grown on the modified surface.
Conjugated Polymer Network Ultrathin Films on Metal Interfaces using the Precursor Polymer Approach: Design, Synthesis and In-situ Characterization
Authors: Advincula Rigoberto , Xia Chuanjun , Taranekar Prasad , Onishi Ken , Deng Suxiang , Baba Akira , Knoll Wolfgang 
Published: April 2011

ABSTRACTWe have reported recently a novel method for cross-linking conjugated polymers involving a “precursor polymer” route, where the electrochemical method can be used to prepare ultrathin films on conducting metal and metal oxide surfaces. In this paper, we present the design, synthesis, protocol, and recent results in the application of these thin film materials. An emphasis will be given on how these films are characterized in-situ by a combined surface plasmon spectroscopy (SPS) and electrochemical approach. As a methodology, the concept can be extended to new methods of electrodeposition, patterning, and grafting of conjugated polymers on electrochemically addressable metal surfaces. Compared to spin-cast or electropolymerized monomer films, they are very robust both thermally and mechanically. Other applications of these films to sensors, dielectric materials, non-lithographic patterning, etc. are currently being investigated.
Plastic Deformation of Glassy Polymers: Correlation Between Shear Activation Volume and Entanglement Density
Authors: Ho Janet , Govaert Leon , Utz Marcel 
Published: April 2011

ABSTRACTThe shear activation volumes of miscible polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) (PS-PPO) blends at different PS-PPO ratios were determined experimentally by both plane strain and uniaxial compression at constant strain rates. We find that the same correlation between the shear activation volume and the entanglement density ρe holds for the blend as well as for various pure glassy polymers: . Since the shear activation volume is closely related to the size of the plastic shear zones, this correlation suggests that the cooperativity of the elementary processes of plastic deformation in glassy polymers scales with the entanglement density.
Oriented Growth of Model Molecules of Polyethylene and Poly(tetrafluoroethylene) (n-C44H90 and n-C24F50) and Angle-resolved UPS Study of Their Intramolecular Energy Band Dispersion (E=E(k)) Relation
Authors: Yoshimura Daisuke , Miyamae Takayuki , Hasegawa Sinji , Hosoi Yukinobu , Sakurai Yoko , Yamamoto Masato , Ishii Hisao , Ouchi Yukio , Ueno Nobuo , Seki Kazuhiko 
Published: April 2011

ABSTRACTWe report on the recent progress of our continued effort for the preparation and characterization of well oriented films of tetratetracontane (n-C44H90) and perfluorotetracosane (n-C24F50), which are good model molecules of fundamental polymers, polyethylene (CH2)n and poly(tetrafluoroethylen) (CF2)n, vacuum-deposited on metal surfaces. When the surface of the metal substrate was oxidized, the deposited chain molecules are aligned with their molecular axes vertically standing on the surface, while they lie flat on the surface when atomically clean Cu(100) surface was used. In the case of n-C44H90 on Cu (100), low-energy electron diffraction (LEED) studies revealed that the molecules were also azimuthally aligned with the chain axis almost parallel with the <100> and <010> axis, and infrared reflection-absorption spectroscopy (IR-RAS) enabled detailed studies of the film structure at increasing film thickness._By applying the technique of angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) to these flat-lying molecules, the intramolecular energy-band dispersion relation could be determined, The results agreed well with the results deduced from the previous work using vertically standing molecules assuming an inner potential V0. of –5 eV, confirming the validity of the estimation of V0. Excellent agreement was found between the observed and simulated spectra using the independent-atomic-center (IAC) approximation. Also the value of the vacuum level shift by molecular deposition was deduced for TTC/Cu(100) system to be – 0.3 eV. As for n-C24F50, the E(k) relation deduced in our previous study using vertically standing molecules showed discrepancy with band calculations. The detailed reexamination of the experimental data using IAC calculations for the previous report gave more realistic estimation of V0, and the newly deduced E(k) relation using this data showed good correspondence with theoretical band calculations, thus removing the difficulty in the previous work.
The Benefits of High-K dielectrics for Polymer TFTs
Authors: Raja Munira , Sedghi Naser , Higgins Simon J. , Eccleston W. 
Published: April 2011

ABSTRACTAn increasing range of high-K dielectric is becoming available and it is very worth considering incorporating them into polymer TFTs. One of the benefits is that if metal gates are used then aqueous anodisation provides a very simple approach that is compatible with solution based processing. The details of this process are described. High-K dielectrics reduce threshold voltage and, therefore, increase switching speed. Of particular importance is the problem of bias instability. All the results involve the fractionation and controlled doping of poly-3-hexylthiophene.
The Direct-Write Polymer Field-Effect Transistor
Authors: Sluch M. I. , Taylor R. M. , Church K. H. 
Published: April 2011

ABSTRACTField-effect transistors (FET's) have been directly written onto glass and Si substrates. The FET';s use the regioregular conjugated polymer poly(hexylthiophene) as the active semiconductor, with a formed polyurethane insulator layer and drain, source, and gate electrodes written in Ag. The FET's were fabricated solely by direct writing techniques. The low processing temperatures, the elimination of photolithography, and the flexibility of the direct writing process make this technology especially attractive for low-frequency applications.
Microwave Characterization Of Electro-Optic Polymers
Authors: Subramanyam Guru , Mathala Prasanna , Chevalier Christine , Davis Antonio , Yaney Perry , Grote James 
Published: April 2011

ABSTRACTElectro-optic polymer thin-films were characterized at microwave frequencies, for possible applications in GHz modulators. Single layers of the polymers were spin coated on low loss magnesium oxide substrates for characterizing the polymers at microwave frequencies. Coplanar waveguide test structures were designed for evaluation of the relative dielectric permittivity as well as the loss-tangent of the polymers at microwave frequencies. A conformal mapping technique was used for the extraction of relative dielectric constant of the polymer films based on the microwave scattering parameter measurements. As an example, a DR1-PMMA polymer had a relative dielectric permittivity of 3.01 and a loss-tangent of 0.075 at 8 GHz. The design of the test structures, the procedure for the accurate determination of the dielectric permittivity and the loss-tangent of the polymer films are discussed in this paper.
Direct-Write Polymer Diodes
Authors: Sluch Mikhail I. , Parkhill Robert L. , Taylor Robert M. , Church Kenneth H. 
Published: April 2011

ABSTRACTConjugated polymer Schottky diodes have been directly written onto glass and alumina substrates. The rectifying contact was made between the p-type semiconductor poly(3,4-ethylene-dioxythiophene) doped with polystyrene sulfonic acid and Zn. The devices exhibit rectification ratios in the range of 102:1 to 103:1 at biases of ±1 V and ±10 V, respectively. The devices demonstrate rectification at frequencies up to 250 kHz. A full-wave bridge rectifier circuit written onto a glass substrate converts ac to dc up to 250 kHz and ±5 V.
Fabrication and characterization of tunable magnetic nanocomposite materials
Authors: Dikeakos M. , Tung L.D. , Veres T. , Stancu A. , Spinu L. , Normandin F. 
Published: April 2011

ABSTRACTFerromagnetic nanocomposites in which magnetic nanoparticles are embedded into a polymeric matrix can replace conventional ferrites in the near future in applications such as: filters, high frequency inductors, chokes, sensors, core-shape and planar transformers, hybrid circuits and transponders. These dense magneto-dielectrics will provide a new approach in the fabrication of soft magnetic materials. In a magnetic/polymeric nanocomposite solid, the resistivity can be drastically increased, leading to significantly reduced eddy-current losses. In addition, the coupling between neighbouring magnetic nanoparticles results in much better soft magnetic properties at high frequencies than those of conventional bulk materials or ferrites. In order to study the influence of dipolar interactions between ferritic nanoparticles, samples of varying ferritic density were prepared. A polymeric binder (pre-swollen in toluene) was added to the nanoparticles, which were then cold-pressed using a standard compaction method. Characterization of the materials was carried out by means of x-ray diffractometry, electron microscopy, magnetometry, and high-frequency complex permeability measurements. Initial results show that tunable static and dynamic magnetic properties of the nanocomposite materials may be achievable.
Comb-Like Polymer Thin Films Prepared by Ionization-Assisted Deposition of Acrylate Compounds
Authors: Usui Hiroaki , Katayama Atsuhiro , Honda Takanobu , Tanaka Kuniaki 
Published: April 2011

ABSTRACTAlkylacrylate compounds were deposited by the ionization-assisted deposition (IAD) method to form thin films of comb-like polymers having long alkyl side chains on the vinyl polymer backbone. From the source material of n-octadecyl acrylate, polymer thin films having average molecular weight of 6000 were obtained at the polymer yield of 45 to 65%. For the preparation of fluorinated polymer thin films, 1H, 1H, 11H-eicosafluoroundecyl acrylate was used as the source material. Although the conventional evaporation method could not accumulate any films with this material, the IAD was able to produce insoluble thin films that have large contact angle against water droplet. In either material, the polymerization reaction was enhanced with increasing electron emission current for IAD. These results indicate that the IAD enables the preparation of thin polymer coatings that have polyethylene or Teflon-like properties without using the solvents.
A TFT Strategy for Polymer Circuits
Authors: Sedghi Naser , Raja Munira , Lloyd Giles C. R. , Liversedge Iain , Higgins Simon J. , Eccleston Bill 
Published: April 2011

ABSTRACTAlthough integrated circuit design principles are well understood, they lead to the possibility of radically new modes of device operation when applied to conjugated polymers. Design for speed is very important, even when this is not a primary requirement for a particular application, since supply voltage can be reduced and with it power dissipation. For all-polymer circuits, on thermally insulating plastic substrates, device operating temperature will also be reduced. This has implications for device stability. There are a number of factors that are important in increasing circuit speed. Reduction of channel length must be accompanied by a reduction of gate overlap capacitance and this makes the conventional versions of bottom gate TFT perform badly. Vertical devices are a particularly attractive proposition providing that off-currents can be maintained at a low level. One approach is to use Schottky barriers as the source and drain. Examples will be explained, as will the very unusual mode of operation of such devices. Optimum load structures will also be defined.
Buckling instabilities of thin cap layers deposited onto low-k dielectric films
Authors: Iacopi F. , Brongersma S.H. , Abell T.J. , Maex K. 
Published: April 2011

ABSTRACTCompressive stresses in thin capping films deposited onto low-k dielectric substrates are particularly prone to relaxation through buckling. This is due to insufficient cap/low-k film adhesion energy and to the compliance of low dielectric constant films. Low-k dielectric films, especially when porous, have low elastic modulus and demonstrate poor adhesion to other layers.When adhesion is poor the cap film can locally buckle as if unconstrained. The buckle front can propagate like a crack and lead to complete delamination of the cap layer. If the cap/low-k film adhesive energy is high, wrinkling instabilities can take place under specific conditions determined by the geometry and the mechanical properties of the stack. In this case the dielectric also deforms due to stress relaxation. A theoretical and experimental evaluation of the parameters influencing the occurrence of these instabilities is presented. This study was carried out to explore the application and reliability of low-k materials as dielectrics for advanced interconnects.
Application Fields of SEM/SPM Hybridsystems: Nanoscopic EBIC and Near Field CL
Authors: Heiderhoff Ralf , Joachimsthaler Ingo , Balk Ludwig J. 
Published: April 2011

ABSTRACTSPM/SEM-hybridsystems are more than only a combination of complementary microscopy techniques, because the used probes can simultaneously either be used as sensors, which give access to a vast variety of material properties, or as actuators, which can deliberately modify samples properties. The wide application field as well as flexibility is demonstrated exemplarily on techniques in microanalyses like nano-probing, cathodoluminescence, electron beam induced currents, and thermal analyses. These results provide an interesting perspective with respect to failure analyses and reliability of modern materials and devices.
Study of doping in GaAs layers by local probe techniques: micro-Raman, micro-photoluminescence and cathodoluminescence
Authors: Ardila Angel M. , Martínez O. , Avella M. , Sanz Luis F. , Jiménez J. , Gérard B. , Napierala J. , Gil-Lafon E. 
Published: April 2011

ABSTRACTThe free carrier concentration of GaAs layers grown by MOCVD either on GaAs or Si substrates, by the conformal method in the last case, was obtained from the micro-Raman spectra using the hydrodynamic approach to fit the LO phonon-plasmon coupled Raman modes. The results on homoepitaxial layers were used as a calibration of the fitting method. The measurements in the selectively doped conformal layers were then compared with data obtained by micro-photoluminescence and cathodoluminescence spectroscopy and imaging. The doping data are compared with those deduced from the room temperature micro-photoluminescence and cathodolumiescence spectra.
High spatial resolution ultrafast scanning tunneling microscopy
Authors: Yarotski Dzmitry , Taylor Antoinette J. 
Published: April 2011

ABSTRACTWe demonstrate ultrafast dynamical imaging of surfaces using a scanning tunneling microscope with a low-temperature-grown GaAs tip photoexcited by 100-fs, 800-nm pulses. We detect picosecond transients on a coplanar stripline and demonstrate a temporal resolution (full-width at half maximum) of 1.7 ps. By dynamically imaging the stripline, we demonstrate that the local conductivity in the sample is reflected in the transient correlated current and that 20-nm spatial resolution is achievable for a 2 ps transient, correlated signal. We apply this technique of photoconductively-gated ultrafast scanning tunneling microscopy to study carrier dynamics in InAs/GaAs self-assembled quantum dot samples at T=300 K. The initial carrier relaxation proceeds via Auger carrier capture from the InAs wetting layer (WL) on a timescale of 1–2 ps, followed by recombination of carriers on a 900 ps timescale. Finally, we demonstrate junction-mixing ultrafast STM (JM-USTM) using picosecond voltage pulses propagating on a patterned metal-on-metal (Ti/Pt). Using JM-USTM we have achieved a spatio/temporal resolution of 1 nm/8 ps.
Scanning Tunneling Optical Resonance Microscopy (STORM)
Authors: Raffaelle R.P. , Gennett T. , Lau J. E. , Jenkins P. , Castro S.L. , Tin P. , Wilt D.M. , Pal A.M. , Bailey S.G. 
Published: April 2011

ABSTRACTThe ability to determine the in-situ optoelectronic behavior of semiconductor materials has become especially important as the size of device architectures is reduced and the development of complex microsystems has increased. Scanning Tunneling Optical Resonance Microscopy or STORM has the ability to interrogate the optical bandgap as a function of position within a semiconductor microstructure. This technique uses a tunable solid-state Ti sapphire laser whose output is “chopped” using a spatial light modulator and is coupled by a fiber optic to a scanning tunneling microscope in order to illuminate the tip-sample junction. The photoenhanced portion of the tunneling current is spectroscopically measured using a lock-in technique. The capabilities of this technique were verified using semiconductor microstructure calibration standards that were grown by organometallic vapor phase epitaxy (OMVPE) at the NASA Glenn Research Center. Bandgaps characterized by STORM measurements were found to be in good agreement with the bulk values determined by transmission spectroscopy, photoluminescence, and with the theoretical values that were based on x-ray diffraction results.
Kelvin Probe Microscopy and Cathodoluminescence Microanalysis of the Irradiation Induced Modification of Insulating Materials.
Authors: Stevens-Kalceff Marion A. 
Published: April 2011

ABSTRACTA combination of Kelvin Probe Microscopy (KPM) and Cathodoluminescence (CL) microanalysis has been used to characterize ultra pure silicon dioxide (SiO2) exposed to electron irradiation in a Scanning Electron Microscope. Charged beam irradiation of poorly conducting materials results in the trapping of charge at pre-existing or irradiation induced defects thereby inducing a localized electric field within the irradiated micro-volume of specimen. The residual surface potentials associated with the localized electric field have been mapped using KPM. Evidence of electro-diffusion and defect micro-segregation in charged beam irradiated SiO2 is observed. The associated mobile defect species are identified using CL microanalysis techniques. The high correlation between KPM and CL images confirms the significant influence of localized potentials on the microstructure of technologically important SiO2.
Nanoindentation: From forces to energies
Authors: Garcia-Manyes Sergi , Gorostiza Pau , Sanz Fausto 
Published: April 2011

ABSTRACTWe have performed nanoindentations using the tip of an AFM cantilever. Experiments have been made on a freshly etched hydrogen terminated Silicon (111) surface, yielding penetrations of less than 1 nm so that the onset of the plastic region(or yield threshold) determination have been carefully investigated. Furthermore, other nanomechanical properties such as hardness have been also investigated. The energy involved in such indentation processes where a nanometric deformation of the surface takes place, has been for the first time calculated by calibration against a non deformable surface, and a correlation with the atomic structure of the indented single crystal is inferred.
FIB-TEM Characterization of Locally Restricted Implantation Damage
Authors: Wanzenboeck Heinz D. , Harasek Stefan , Brezna Wolfgang , Lugstein Alois , Langfischer Helmut , Bertagnolli Emmerich , Grabner Ulf , Hammer Gerold , Pongratz Peter 
Published: April 2011

ABSTRACTImaging critical features by using transmission electron microscopy (TEM) or scanning electron microscopy (SEM) provides a versatile approach for nanostructure characterization. The combination of focused ion beam (FIB) technology for exposing defective sites beneath the surface is shown. Reliability testing and defect analysis by localized characterization of multilayered structures is demonstrated. TEM-imaging of a transistor gate with a locally confined radiation damage demonstrates target preparation by FIB yielding high-resolution TEM samples. The TEM imaging requires a longer sample preparation but provides high image quality (TEM). Investigation of materials previously processed with FIB revealed amorphization damage by the high energetic Ga-ion beam. This damage layer with a thickness in the range of 50 to 100 nm was confirmed in simulation. This disadvantageous damage by amorphization originating from FIB preparation of the cross-section could be removed by soft sputtering with a 250 V Ar+ion beam. This combined method using FIB for microsample preparation and TEM for imaging and analysis was proven to be a powerful tool the exploitation of nanostructured devices and for defect analysis on a highly localized scale.
Location of Current Carrying Faults in Integrated Circuits by Magnetic Force Microscopy
Authors: Pu A. , Rahman A. , Thomson D.J. , Bridges G.E. 
Published: April 2011

ABSTRACTIn Integrated Circuits failure analysis excessive power supply current flowing into the IC is often used to indicate the presence of a faulty device. Location of these faulty devices can be problematic as the devices are often buried under several layers of conducting interconnect. By imaging the magnetic field produced by current flowing in an IC a faulty device can be located. In this paper we present experimental results on imaging current-carrying faults on integrated circuits using Magnetic force microscopy. We have experimentally determined that MFM is capable of measuring currents as small as 1 to 10 microampere on ICs in a 30 Hz bandwidth. We have carried out modeling calculations comparing the simulation results with experimental results using realistic MFM tip geometry. From these results we have devised a method to accurately locate the position of the internal current carrying faults from MFM images with micrometer uncertainty.
STM Light Emission from p-type GaAs (110) surface
Authors: Hoshino M. , Yamamoto N. 
Published: April 2011

ABSTRACTSTM stimulated light emissions (STM-LE) from cleaved surfaces of GaAs(110) were investigated using a UHV-STM combined with a light detection system. Clean surfaces of Zn doped GaAs (p=5×1018) were obtained by mechanical cleavage in UHV. Light emission from the cleavage surface showed a single peak in a spectrum, which corresponds to luminescence by the conduction band to acceptor level transition in GaAs. In STM image Zn acceptors show bright tri angular-shaped contrasts, while in photon map they show dark contrasts when taken with a sample bias voltage of 2.0 V and 2.2 V at 80K. This contrast can be explained from the local band bending due to the charging effect or strain effect of the Zn acceptor.