bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Conformation-dependent Memory Effects in Non-conjugated Polymers with Pendant Carbazole Moieties
Authors: Lim Siew Lay , Ling Qidan , Teo Eric Yeow Hwee , Zhu Chun Xiang , Chan Daniel Siu Hung , Kang En Tang , Neoh Koon Gee 
Published: April 2011

AbstractSingle-layer devices of the structure indium-tin-oxide/polymer/aluminum were fabricated from two non-conjugated polymers with pendant carbazole groups in different spacer units. The device based on poly(2-(N-carbazolyl)ethyl methacrylate) (PMCz) exhibited non-volatile write-once-read-many-times (WORM) memory behavior with an ON/OFF current ratio up to 106, while the device based on poly(9-(2-((4-vinylbenzyl)oxy)ethyl)-9H-carbazole) (PVBCz) exhibited volatile memory behavior with an ON/OFF current ratio of approximately 103. In the absence of a spacer unit between the pendant carbazole group and the main chain, regioregular poly(N-vinylcarbazole) (PVK) exhibited only one conductivity state (ON state). The switching and memory effects observed were attributed to conformation changes of the pendant carbazole groups.
Small Molecular Organic Nonvolatile Memory Fabricated with Ni Nanocrystals Embedded in Alq3
Authors: Oh YoungHwan , Nam WooSik , Lee GonSub , Park JeaGun , Lee YongBok 
Published: April 2011

AbstractRecently, organic nonvolatile memory has attracted much interest as a candidate device for next generation nonvolatile memory because of its simple process, small device area, and high speed. To investigate electrical characteristics of small molecular organic nonvolatile memory with Ni as a middle metal layer, we developed a small molecular organic nonvolatile memory with the device structure of Aluminum tris (8-hydroxyquinolate) (Al/Alq3), Ni nanocrystals, and Alq3/Al. A high vacuum thermal deposition method was used for the device fabrication. It is critical that the fabrication process condition for Ni nanocrystals be optimized, including ∼100 Å thickness, 0.1 Å/sec-evaporation rate, and in-situ plasma oxidation for effective oxidation. The reasons we chose Ni for the middle metal layer are that Ni has a smaller grain boundary, which is beneficial for scaling down and has a larger work function (∼5.15 eV) that can make a deep quantum well in an energy band diagram, compared with that of Al. Our device showed an electrical nonvolatile memory behavior including Vth of ∼2 V, Vw (write) of ∼3.5 V, negative differential region (NDR) of 3.5∼7 V, Ve (erase) of 8 V, and symmetrical electrical behavior at reverse bias. In addition, an interesting behavior of electrical properties was that, although retention and endurance characteristics were similar to the Al device, the Ion/Ioff ratio was greater than 104 at Vr (read) of 1 V. This value of the Ni device was higher than 102 compared to that of the Al device. Also, small molecular organic nonvolatile memory with a Ni middle layer with α-NPD at same fabrication condition showed more unstable characteristics than Alq3. We can speculate that there is a relationship in fabrication condition between the middle metal material and the organic material. Finally, we conclude that our device with a Ni nanocrystals middle layer is more reliable and useful for small molecular organic nonvolatile memory.
Germanium ALD/CVD Precursors for Deposition of Ge/GeTe Films
Authors: Hunks William , Chen Philip S. , Chen Tianniu , Stender Matthias , Stauf Gregory T. , Maylott Leah , Xu Chongying , Roeder Jeffrey F. 
Published: April 2011

AbstractIn order to deposit conformal films in the high aspect ratio trench and via structures in future high-density phase-change memory devices, suitable ALD/CVD precursors are needed. We report on the development of novel germanium(II) metal-organic ALD/CVD precursors containing amide, cyclopentadienyl, and amidinate ligands. The physical properties, volatility, and thermal behavior of the precursors were evaluated by simultaneous thermal analysis (STA) and vapor pressure measurements. Stability studies were conducted to investigate the suitability of the precursors for use as ALD/CVD precursors for device manufacturing.
Observation of the transition from tunneling to hopping carrier transport through single oligothiophene molecules
Authors: Yamada Ryo , Kumazawa Hiroaki , Tanaka Shoji , Tada Hirokazu 
Published: April 2011

AbstractElectrical conductance of single oligothiophene molecules with a length in the range from 2 to 9 nm was measured as a function of molecular length by a break junction method. The resistance of oligothiophenes increased exponentially from 5-mer to 14-mer while that of molecules longer than 17-mer showed linear dependence on their length. These results indicated that the carrier transport mechanism changed from tunneling to hopping around 14-mer of which the length is approximately 6 nm.
Low Leakage Current Patterned Polymeric Transistors with PAG Assisted Cross-linking PVP as Gate Dielectric and Passivation Layers
Authors: Liu Cheng-Chin , Chang Kuo-Jui , Yang Feng-Yu , Liao Ta-Chuan , Cheng Huang-Chung 
Published: April 2011

AbstractWe have successfully proposed a patterned P3HT thin-film transistor with cross-linked PVP as a passivation material which was cured at low temperature. The active P3HT layer was isolated via photolithographic technique and O2 plasma RIE etching process. In this method, the leakage current could be reduced effectively compared with that of non-patterned device. Although the mobility was degraded 40 %, but the on/off ratio was significantly improved by over three orders and also the subthreshold swing was compatible with the amorphous Si-TFTs (∼1.5 V/decade). Moreover, we also employed this low temperature curing PVP (120 0C) films as the gate dielectrics which exhibited excellent insulating property with high on/off ratio 1.58×104 and good subthreshold swing 1.66 V/decade.
In-crystal Carrier Transport in Organic Single Crystal Transistors
Authors: Takeya Jun , Yamagishi M. , Tominari Y. , Iwasaki Y. , Uno M. 
Published: April 2011

AbstractWe report a series of our experiments using organic single crystals to reach the maximum performance intrinsic to the materials. A consequence of the experiments is that a prescription for realizing high-mobility devices is to induce carriers in inner crystals to avoid scattering at the surfaces. Intrinsic-semiconductor character of the high-purity organic crystals favors thermal diffusion of the carriers into the crystals in the presence of weak gate-electric fields. Furthermore, it is demonstrated that the high-mobility transport of the in-crystal carriers are highlighted in double-gate single-crystal transistors with the two gate electric field balanced with each other.
Influence of Grain Interaction on the Mechanical Behavior in Shape Memory Material in Flexion Test
Authors: Cortés Jacinto , García Fernando N. , González José G. , Flores Horacio , Reyes Alberto 
Published: April 2011

ABSTRACTAn experimental study of the mechanical properties of a Cu-Al-Be shape memory alloy is presented. The samples are tested in a cantilever arrangement. They consist of polycrystalline thin plates of shape memory material with a MS near 0 °C and a monocrystalline sample with MS near −90 °C. The measurements are made with strain gauges attached to the top side of the samples. In these conditions, strain Vs load curves are obtained. A polycrystalline sample is instrumented and tested and then it is cut into three samples for further testing. The results show a relationship between the transformation stress and the sample grain size which differs from the typical Hall-Petch relationship. The analysis of transformation plane stress diagrams shows the development of a stress component perpendicular to those induced by the applied load.
Synthesis and Characterization of Polyurethane Scaffolds for Biomedical Applications
Authors: Chavarría-Gaytán M.C. , Olivas-Armendáriz I. , García-Casillas P.E. , Martínez-Villafañe A. , Martínez-Pérez C. A. 
Published: April 2011

ABSTRACTPolyurethanes are interesting materials that can be used in biomedical applications for regeneration of bone tissue. In this work the synthesis and characterization of porous polyurethanes to act as scaffold is performed by a thermally induced phase separation technique. The appropriate parameters are determined in order to obtain a porous well interconnected material. Characterization by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is made in order to determine the thermal stability of the material. Chemical characterization is made by Fourier transformed infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The morphology of the material is observed by a field emission scanning electron microscope (FESEM) and the mechanical properties are measured by dynamic mechanical analysis (DMA).
Physical Modeling of Gas Jet-Liquid Free Surface in Steelmaking Processes
Authors: Solórzano-López J. , Zenit R. , González-Rivera C. , Ramírez-Argáez M. A. 
Published: April 2011

ABSTRACTGas jets play a key role in several steelmaking processes as in the Basic Oxygen Furnace (BOF) or in the Electric Arc Furnace (EAF). They improve heat, mass and momentum transfer in the liquid bath, improve mixing of chemical species and govern the formation of foaming slag in EAF. In this work experimental measurements are performed to determine the dimensions of the cavity formed at the liquid free surface when a gas jet impinges on it as well as liquid velocity vector maps measured in the zone affected by the gas jet. Cavities are measured using a high speed camera while the vector maps are determined using a Particle Image Velocimetry (PIV) technique. Both velocities and cavities are determined as a function of the main process variables: gas flow rate, distance from the nozzle to the free surface and lance angle. Cavity dimensions (depth and diameter) are statistically treated as a function of the process variables and also as a function of the adequate dimensionless numbers that govern these phenomena. It is found that Froude number and Weber number control the depression geometry.
Heat Treatment Effect on Properties of Ni-P-Al2O3 Composite Coatings
Authors: León-Patiño Carlos A. , García-Guerra Josefina , Aguilar-Reyes Ena A. , Lemus-Ruiz José 
Published: April 2011

ABSTRACTNi-P and Ni-P-Al2O3 composite coatings are obtained by electroless plating on steel substrates. Alumina particles with an average particle size of 5 microns are added to the bath in loads of 5, 10, 15 and 20g/L. It is found a maximum retention of 18.2 vol.% Al2O3 for a ceramic load of 10g/L. The composition of the binary Ni-P deposits is 9.3 wt.% P and the balance nickel. The addition of ceramics to the electroless solution induces a reduction of phosphorous content to 9.0, 8.3, 7.9 and 7.3%, respectively. The deposited coatings are heat-treated in the temperature range between 100 and 500°C and holding times from 30 to 300 minutes. A maximum hardness of 1600 HV0.1 is obtained for composite coatings containing 18.2 vol.% Al2O3 treated at 400 °C/1h. The uniform distribution of ceramics and precipitation of fine Ni3P and Ni12P5 precipitates are responsible of the hardening of the nickel matrix.
In-Situ Dynamic High-Resolution Transmission Electron Microscopy Investigation of Guest-Layer Behavior During Deintercalation of Mercury Titanium Disulfide
Authors: Mckelvy M. , Sidorov M. , Marie A. , Sharma R. , Glaunsinger W.S. 
Published: April 2011

ABSTRACTDeintercalation processes for the model neutral intercalation system HgxTiS2 (1.25≥x>0.00) have been investigated using dynamic high-resolution transmission electron microscopy. X-ray powder diffraction and thermogravimetric analysis demonstrated the intercalation process is thermally reversible, both structurally and compositionally. In situ deintercalation of stage- 1 compounds was induced by thermal/electron-beam heating during DHRTEM observation. The resulting deintercalation processes were followed with 0.03 second time resolution. The deintercalation processes observed possess a strong similarity to nucleation and growth processes. Deintercalation was observed to “nucleate” by the initial deintercalation of an external-most or internal guest layer, with further deintercalation of the guest “growing” away from the onset layers. This results in generally randogmuelsyt lsatyaegresd greengeiroanllsy, occasionally containing regions of short-range order, that expand away from the deintercalation onset layers.
Moire Patterns in High Resolution Electron Microscopy Images
Authors: Reyes—Gasga J. , Tehuacanero S. , Zorrilla C. 
Published: April 2011

ABSTRACTMoiré patterns are so often observed in the HREM images and they could be mistaken as the direct image of the atomic structure of the sample under analysis. In this workwe presented some examples of these patterns and their computer graphic simulations.
Polarization, Interference Contrast, and Photoluminescence Imaging in Near Field Optical Microscopy
Authors: Vaez-Iravani M. , Toledo-Crow R. , Rogers J.K. 
Published: April 2011

ABSTRACTThe design and operation of a number of techniques in near field optical microscopy are described. Specific attention is paid to the three modalities of polarization, interference contrast, and photoluminescence imaging. By premodulating the polarization state of the sample beam, pure, linear, polarizing microscopy is performed. In addition, polarization anomalies are observed in the focal plane of a high numerical aperture lens. Amplitude and phase contrast imaging is performed in a feedback stabilized Mach-Zehnder interferometer. Magneto-optically induced polarization shifts are detected interferometrically, resulting in linear sensitivity. Localized photoluminescence is induced in porous silicon, and the results are correlated with the topography of the sample.
Photon Tunneling Microscopy Applications
Authors: Guerra John M. 
Published: April 2011

ABSTRACTWith photon tunneling microscopy (PTM), dielectric, semiconductor, and other surfaces are imaged by means of the phenomenon of photon tunneling (or evanescent waves). Vertical resolution is detector limited to one nanometer and the vertical range is λ/2. Lateral resolution is better than λ/4 with a field-of-view up to approximately 125 µm. PTM produces images of samples independent of size and thickness in real-time without metallization, shadowing, vacuum, electrons, or scanning probes. Tunneling images are analog processed for realtime 3-D topographic imaging with continuous viewpoint and magnification control. In this paper PTM images of a variety of samples are presented and briefly discussed.
Electronic Structure of Layered and Linear Chain Materials by Scanning Probe Microscopy
Authors: Coleman R.V. , Dai Z. , Gong Y. , Slough C.G. , Xue Q. 
Published: April 2011

ABSTRACTTransition metal impurities such as Fe, Ni, and Co can be intercalated into the van der Waals gap of layer structure dichalcogenides and these modify the charge-density wave (CDW) structure and CDW energy gaps. Ordered superlattices associated with antiferromagnetic phases can be detected by both scanning tunneling microscopy (STM) and atomic force microscopy (AFM). STM spectroscopy indicates the formation of a mixed spin-density-wave (SDW) and CDW (SDWCDW) in the doped materials. The quasi-one dimensional trichalcogenide NbSe3 exhibits two CDW transitions and the presence of dilute transition metal impurities produces ordered superlattices due to long range screening of the impurities.
Tensile Deformation-Induced Microstructures in Freestanding Copper Thin Films
Authors: Keller R. R. , Phelps J. M. , Read D. T. 
Published: April 2011

ABSTRACTExisting work in the mechanical behavior of thin films focuses mainly on measurement of macroscopic properties without strong correlation to microstructural features. We used transmission electron microscopy (TEM) to characterize the microstructures of free-standing copper thin films both before and after monotonic tensile deformation in an ex-situ thin film tensile testing system, as well as during in-situ loading in the TEM. The defect structures contributing to plastic deformation were investigated with an emphasis on comparison to mechanisms known to operate in bulk copper. The thin film exhibited much lower ductility (approximately 1%) than that normally observed in bulk form (greater than 40%). The predominant plastic deformation mechanisms did not include the typical dislocation activity that occurs in bulk copper, but rather greatly inhibited dislocation interactions typical of stages I and II hardening only. The absence of those structures normally found in tensile-deformed bulk copper is attributed to the differences in characteristic sizes of features within the microstructure available for deformation in bulk versus evaporated thin film material, that is, grain size and film thickness. The thin film ductility is an order of magnitude lower than what has been observed in bulk, ultrafine-grained copper, implying that a pure thin film effect on ductility exists and is significant. Microstructural features both near to and far from the fracture surface regions will be presented.
Effects of Thin Film Stress in Sub Micron Multilevel Devices
Authors: Prasad Sharad , Lu Y.C. , Li D.K , Reddy G.S. , Chen F. 
Published: April 2011

ABSTRACTSubmicron high density devices require multilevel interconnections. In multilevel interconnections, issues relating to planarity, stress voiding of metals and stress cracking of the dielectric(s) play an dominant role.As the levels of interconnect go up so does the stress level. A high stress level in the intermediate dielectric can cause cracks which ultimately lead to device failure. In this paper we present a novel method to detect stress cracking using focussed ion beam. This method is correlated with wet chemical etch process and RIE.The phenomenum of cracking of dielectric(s) is studied and different technology aspects are considered. Using the focussed ion beam a robust dielectric is developed.
Epitaxy of Erbium Doped LiNbO3 Films Produced by Pulsed Laser Deposition
Authors: Bauer S. , Beckers L. , Fleuster M. , Schubert J. , Zander W. , Buchal Ch. 
Published: April 2011

AbstractThe growth of thin films of LiNbO3 and Er:LiNbO3 on LiNbO3 single crystals produced by pulsed laser deposition (PLD) was studied. Samples were characterized by RBS/Channeling Spectrometry, X-ray diffraction measurements, Secondary Ion Mass Spectroscopy (SIMS) and photoluminescence (PL) measurements. Film preparation is performed in a two-step process including deposition and in-situ-annealing. Buried Er doped layers of approx. 800 nm thickness were grown.
C− Outgrowths in C+ Thin Films of LiNbO3 on Al2O3-c
Authors: Kingston J. J. , Fork D. K. , Leplingard F. , Ponce F. A. 
Published: April 2011

AbstractThin-film waveguides of LiNbO3 have been grown on Al2O3-c by off-axis rf magnetron sputtering. The films have been characterized optically by prism coupling measurements, crystallographically by x-ray diffraction, and morphologically by atomic force microscopy. We find that optical losses can be dominated by scattering from large outgrowths that litter the surface of the film. These outgrowths are c− grains imbedded in a c+ matrix. Although some grains nucleate c−, others have their polarity reversed from c+ to c− after nucleation. A model will be presented to explain the preferential nucleation of c+ grains on Al2O3-c. The c− grains grow much faster than the c+ ones because of attractive coulombic forces between the c− grains and the ionized Li and Nb species in the sputter plume.
BaTiO3 Thin Films Prepared By Dip-Coating Process
Authors: Della Nelcy , Mohallem Santina 
Published: April 2011

AbstractThin films of pure barium titanate have been prepared by the sol-gel process from organomettalic sols containing titanium alkoxides and barium acetate (molar ratio [Ba]/[Ti]=l). It leads to transparent, homogeneous and adherent coatings. The influence of various parameters such as chemical concentration, viscosity, withdrawal speed and temperature of densification on film thickness is described. The films were characterized by X-ray diffraction during their heat treatment. Their crystallization temperature was observed to be around 450°C. No variations in the optical properties were observed during the crystallization, and it occurred without the appearance of cracks or pinholes. Tetragonal BaTiO3 structure was observed, and the ferroeletric properties were investigated as functions of thickness and grain size.
Homogeneity of Wet Oxidation by RTP
Authors: Glück M. , König U. , Hersener J. , Nenyei Z. , Tillmann A. 
Published: April 2011

ABSTRACTThe implementation of a wet oxidation process in an RTP system using a bubbler with deionized water is described. A special process related calibration in a wet atmosphere, by means of pyrometer and thermocouple readings, allows one to improve the temperature accuracy during the oxidation to an offset of only + 1 to 2°C. High oxide growth rates, up to a factor of 1.8 above literature data have been achieved. Wet and dry RTO oxides are compared and related to the expectations from growth models. Effects of growth time (10 s to 4 min), growth temperature (675°C-950°C), substrate orientation (100,111), preparation (e.g. HF) and bubbler temperature (20°C-90°C) are presented. The uniformity of oxides on 4 and 6 inch diameter wafers are discussed. Preferentially by the use of a silicon guard ring and by adjusting lamp power and gas flow rates excellent results concerning uniformity (standard deviations 2σ: 1-2 %) and reproducibility (variation of 0.5 to 0.75 % at least over 12 wafers) are obtained.
Gas Flow Engineering in Rapid Thermal Processing
Authors: Nényei Z. , Sommer H. , Gelpey J. , Bauer A. 
Published: April 2011

ABSTRACTGas flow engineering involves gas dynamics optimization for effective ambient change before heating and for homogeneous convective cooling of the wafers during the heating steps. Multiple gas buffle system, dynamical gas handling, low pressure operation, low temperature edge guard ring and independent top and bottom heater bank control are the proper tools for this optimization. Silicon surface or interface damage during inert gas anneal can be avoided by addition of a small amount of oxygen.
Influence of H2 on Ge Surface Segregation in Si/SiGe Heterostructures Grown by RTP/VLP-CVD
Authors: Rong Zhang , Hongbin Huang , Shulin Gu , Kai Yang , Yi Shi , Ronghua Wang , Youdou Zheng , Duan Feng 
Published: April 2011

ABSTRACTIn this paper we report the influence of H2 on Ge surface segregation in Si/SiGe heterostructures. The sample were grown on Si(001) substrate tinder different gas flow of H2 by RTP/VLP-CVD. Auger electron energy spectroscopy(AES) has been used to determine the Ge distribution in Si/SiGe heterostructures. The results indicate that H2 can strongly alter the mechanism of Ge surface segregation and change the distribution of Ge atoms.