bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishment of Reaction Phase Diagrams of Pseudo Quaternary Li-Ni-Co-Ti Oxides Library
Authors: Fujimoto Kenjiro , Onoda Kazuhiro , Ito Shigeru
Published: April 2011

Reaction phase diagram of pseudo four-components Li-Ni-Co-Ti oxides was established for finding new chemical composition and functional materials by the combinatorial high-throughput preparation system “M-ist Combi,” based on electrostatic spray deposition process and the combinatorial x-ray powder diffraction apparatus. The new layered-type compounds were found wider composition region than the previous reported composition region of LiNi0.8-yCo0.2TiyO2 (0≤y≤0.1). Furthermore, the new composition regions of single phase for spinel-type and rock salt-type compounds in pseudo four-components Li-Ni-Co-Ti oxides system were also found in a short time.
Combinatorial Approach for Thermoelectric Materials through Bulk Composition-Spreads and Diffusion Multiples
Authors: Yamamoto Atsushi , Noguchi Teruo , Obara Haruhiko , Ueno Kazuo , Ikeuchi Satoaki , Sugawara Tooru , Shimada Kenji , Takasaki Youichi , Ishii Yoshikazu
Published: April 2011

In this paper we describe a new attempt of high-throughput screening of thermoelectric materials by combining the use of the “bulk composition-spread (CS)” or “bulk diffusion multiples (DM)” and the “scanning thermal probe microanalyzer (STPM).” The (Bi2Te3)1-x(Sb2Te3)x (0<x<1) and Ni1-xCux (0<x<1) bulk CS samples were prepared by conventional powder metallurgy method by using mechanical alloying and spark plasma sintering process. The Ni-Cu-X (X=Sn, In, Bi.) DM sample was prepared by post-heating of the CS samples in a molten metal. The two dimensional distributions of Seebeck coefficient and the thermal conductivity of the cross section of the CS and DM samples which composed of graded composition were visualized by using STPM at room temperature. The composition variation was checked by EDX. The relationship between composition and the thermoelectric properties was successfully determined by using the mapping results. The time required for mapping out the 100x100 pixel image was 8 to 11 hours. The total time required for this set of the screening experiment, from sample preparation to the final conclusion, was within 24 hours. For samples Ni-Cu-X DM the diffusion length of the elements at the interface can be large as 1mm and it was found that STPM is applicable to visualize the thermoelectric properties at the region of interest.
Basic Research on Combinatorial Evaluation Method for Coefficient of Thermal Expansion
Authors: Aono Yuko , Hata Seiichi , Sakurai Junpei , Yamauchi Ryusuke , Tachikawa Hiroyuki , Shimokohbe Akira
Published: April 2011

The coefficient of thermal expansion (CTE) is one of the most important material properties for actuators driven by heat or structure over a wide temperature. The CTE of an alloy depends on its composition, and combinatorial methods are very effective for researching new alloys. A CTE evaluation method, which can be applied to combinatorial methods or a thin film library, is proposed in this paper. The thermal behavior of a bi-layer cantilever couple was used for the evaluation, and the Young's modulus, which is also an important property, was simultaneously obtained. Firstly, one bi-layer cantilever was fabricated and agreement of the thermal behavior with the theoretical behavior was confirmed. The estimated error of the measurement device (CCD camera) resolution was then analyzed. The results indicate that combinatorial evaluation does not enable an accurate evaluation of Young's modulus, but does allow the CTE be accurately determined.
Determination of strain within Si1-yCy layers grown by CVD on a Si Substrate
Authors: Cherkashin Nikolay , Gouye A. , Hue F. , Houdellier F. , Hytch M. J. , Snoeck E. , Paillard V. , Kermarrec O. , Rouchon D. , Burdin M. , Holliger P. , Claverie A.
Published: April 2011

In this work, we performed quantitative measurements of strain in structures consisting of a 30 nm-thick Si1-yCy layer grown by chemical vapour deposition (CVD) on a Si (001) substrate at 550 or 600°C. The total C concentration varies from 0.67 to 1.97% that was measured by SIMS. Geometric phase analysis (GPA) of high resolution transmission electron microscopy (HR TEM) cross-section images and convergent beam electron diffraction (CBED) were used to deduce the strain within these Si1-yCy layers. Finite-element simulations were carried out to estimate the impact of strain relaxation in thin areas of a specimen. These results were compared with the data obtained by high resolution X-ray diffraction and Raman spectroscopy and with the predictions of elasticity theory. Particular interest is paid to the formation of the structural defects within Si1-yCy layers as a function of a C concentration, growth temperature and incorporated strain. Both cross-sectional and plan-view TEM specimen configurations were used to obtain quantitative information on the defect size distribution, their density and structure.
Aberration-corrected HRTEM of the Incommensurate Misfit Layer Compound (PbS)1.14NbS2
Authors: Garbrecht Magnus , Spiecker Erdmann , Jäger Wolfgang , Tillmann Karsten
Published: April 2011

The development of tunable spherical aberration (Cs) imaging correctors for medium-voltage transmission electron microscopes (TEM) offers new opportunities for atomic-scale in-vestigations of materials. A very interesting class of microstructures regarding a variety of dif-ferent physical properties are the transition metal dichalcogenide misfit layer compounds exhibit-ing a high density of incommensurate interfaces due to their stacked nature. In the present study, the benefits coming along with the set-up of negative CSimaging (NCSI) conditions (in TEM) are demonstrated by means of different examples regarding local inhomogeneities in (PbS)1.14NbS2crystals that can not be dissected in such detail by averaging x-ray techniques.
TEM and STEM study of the Au nano-particles supported on metal oxides
Authors: Akita Tomoki , Tanaka Koji , Kohyama Masanori , Haruta Masatake
Published: April 2011

The Au nano-particles are deposited on the metal oxide substrate, TiO2 and CeO2, and the structure of the Au particles and Au-metal oxide interface was observed by TEM and HAADF-STEM. It was found that the growth of Au particles on TiO2 and CeO2 by heating treatment is suppressed in the reductive atmosphere. The HAADF-STEM observation was carried out and the atomically resolved HAADF-STEM images in profile-view are successfully obtained for Au/TiO2 and Au/CeO2 samples. The Au particles tend to supported on CeO2 surface with the flat interface compared to the TiO2 substrate. The incoherent interface is observed for the Au particles-CeO2 interface.
Study of Elastic Behavior of Metallic Thin Films by 2D Synchrotron XRD and in situ Tensile Testing
Authors: Guillaume Geandier , Pierre-Olivier Renault , Philippe Goudeau , Le Bourhis Eric , Baptiste Girault
Published: April 2011

Understanding the mechanical behaviour of nano-structured thin films in relation to their structure, in particular to the grain size, is of high importance for the development of technological applications. Model nanometric multilayer W/Au systems exhibiting different structures are elaborated. These films are supported by a (thin) polyimide substrate. Films mechanical response is characterized experimentally by tensile tests carried out in-situ in a X-ray diffractometer installed on a synchrotron source. X-ray diffraction in transmission geometry has been used to study the deformations of both phases as a function of applied load. This geometry has been developed in the aim of optimizing the experiment time.
Electronic Structures of Dyes and Phthalocyanines Estimated with “Photo-Electron Spectroscopy in Air (PESA)”
Authors: Nakajima Yoshiyuki , Yamashita D. , Ishizaki A. , Pellissier B. , Uda M.
Published: April 2011

The near-edge electronic structures of several dyes and phtalocyanines were investigated using Photo-Electron Spectroscopy in Air (PESA). The ionization potentials (IPs) of N3, N719, Z907, D102, D149 and D205 were derived from observed photoemission threshold energies to be 5.88, 5.47, 5.44, 5.53, 5.44 and 5.49eV, respectively. Density of states (DOS) of Fe-, Ni-, Cu- and H2-phthalocyanines were deduced from differentiation of observed photoemission yields with incident photon energies. DOS thus obtained were well compared with calculated ones estimated with use of the DV-Xα molecular orbital calculation method.
Photoemission Investigation of the Energy Level Alignment at the Rubrene/metal Interface
Authors: Ding Huanjun , Gao Yongli
Published: April 2011

The electronic structure of the interfaces between rubrene and various metals, including Au, Ag, Al, and Ca, have been investigated with photoemission and inverse photoemission spectroscopy. The formation of the interface dipole is observed at all interfaces. The Fermi level shifts linearly within the band gap as a function of metal workfunction, until it is pinned at the lowest unoccupied molecular orbital (LUMO) by Ca. Strong interactions take place at the interface between rubrene and Ca, evidenced by the evolution of the valence features.
Improving Stability of Pentacene Field-Effect Transistors with Post-Annealing
Authors: Liu Shun-Wei , Huang Jia-Cing , Lee Chih-Chien , Lee Chin-Ti , Wang Juen-Kai
Published: April 2011

In this report, we demonstrate that the performance and stability of pentacene top-contact field-effect transistor can be greatly improved with post-annealing treatment. After post-annealing at 90°C for 12 hours in nitrogen environment, the hole field-effect mobility of 0.3 cm2/Vs and the on/off current ratio of 107 were achieved, demonstrating 100% improvement in performance after the post-annealing treatment. The decay rate of drain current at constant gate and drain-source voltage was found to be decreased by more than 40%. The improved performance is attributed to the elimination of trapped holes and lattice defects in the organic semiconductor layer due to the post-annealing process.
Ion Beam Deposition from Colloidal CdSe/ZnS Nanocrystals Solutions for Fabricating Electroluminescent Device
Authors: Tani Yuki , Kobayashi Satoshi , Kawazoe Hiroshi
Published: April 2011

We have already reported AC-drive CdSe/ZnS quantum dot (QD) inorganic electroluminescent (EL) devices from colloidal solution. The EL spectra of the devices reproduced photoluminescent spectra of the source QD solutions. Furthermore, the observation of time resolved luminescent properties in ambient atmosphere at room temperature, are analyzed for improvements and projection of brightness and efficiency. The results suggest that the lifetimes of excited states in quantum dots are affected by the electric field in the electroluminescent devices.
Efficient Thin Polymer Solar Cells with Post-Annealing
Authors: Liu Shun-Wei , Lee Chih-Chien , Huang Ping-Tsung , Chen Chin-Ti , Wang Juen-Kai
Published: April 2011

The authors report the study of the dependence of the device performance of polymer solar cells based on single 50-nm heterojunction poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methylester (P3HT/PCBM) layer on annealing process. Annealing before and after cathode deposition were performed for comparison. In the case of post-annealing at 150¢XC for 60 min., the device attains a conversion efficiency of 4.9%, a fill factor of 53 %, and an open-circuit voltage of 0.67 V. These values are comparable with the highest values reported previously. The annealing process is expected to modify the network morphology of the P3HT/PCBM layer. This study demonstrates that it is possible to attain good solar cell performance with the combination of single thin active layer and post-annealing treatment. This may open up an opportunity to fabricate tandem polymer solar cells.
Magnetometric Measurements of Ferro- or Ferrimagnetic Microparticles Dispersed in Medium Approximating the Intracellular Environment
Authors: Jurdak Peter , Kopani Martin , Šimacek Ivan , Manka Jan , Škrátek Martin
Published: April 2011

Relaxation of the remanent magnetization produced by samples with magnetized ferromagnetic micro-particles dispersed in a liquid non-ferromagnetic material was measured. The intracellular environment was simulated by liquid with two various viscosities. Using the SQUID gradiometric system the time-dependences of the relaxation on the intensity of the magnetizing field and the viscosity of non-magnetic carrier liquid have been investigated. Since the relaxation is always present after the magnetizing process, the time-dependences of the relaxation has to be measured for the correction of resulting data in the realistic evaluation of the ferromagnetic contamination of retained dust in the lungs (magnetopneumography), in the magnetic measurement of human iron stores in the liver and it can be also successfully applied in a magnetopneumographic investigation of alveolar clearance.
Self-organization of magnetic nanogroove arrays by LaserMBE and hydrogen reduction.
Authors: Matsuda Akifumi , Watanabe Takahiro , Akita Yasuyuki , Hosaka Makoto , Koyama Kouji , Takeuchi Atsuko , Yoshimoto Mamoru
Published: April 2011

The epitaxially grown magnetic nanostructures including nanodots, nanowires and nanorings have been attracting much scientific and engineering interests because of their expected unique physical characteristics due to quantum effects. These epitaxial nanomagnets and their array are undoubtedly thought to make major contribution to the development of future SPINTRONICS devices, ultra-high density magnetic random access memory (MRAM) and magnetic switching devices for examples, and other quantum devices. In this case, epitaxial growth of the nanomagnets and the resulting anisotropic properties are one of the largest interest as well as fine-nanostructuring. There have been some concerns such as throughput rate with conventional nanoprocessing techniques involving FIB lithography and e-beam lithography, and/or minimization-limit with photolithography due to the wavelength. On the other hand, self-assembly or self-organized methods could also be used for construction of nanopatterns, in which such nanostructures are directly built up from separate atoms. Here we report about formation and characterization of self-organized nanomagnet arrays made of metals and oxides. We have epitaxially grown ferrimagnetic Fe3O4 (111), (Mn0.55Zn0.35Fe0.10)Fe2O4 (111), ferromagnetic Ni (111) and antiferromagnetic NiO (111) nanodots, nanowires and nanogroove arrays on the atomically stepped ultra-smooth sapphire (0001) substrate by LaserMBE. The sapphire (a-Al2O3single crystal) substrates have atomic steps of 0.2 nm in height and atomically flat terraces of 50-100 nm in width so that self-assembly processes of nanomagnet arrays were strongly induced by the energetic instability at the straight and periodic step-edges. In this study, NiO worked as a antiferromagnetic exchange bias layer. On the other hand, NiO was also reduced into ferromagnetic Ni metal by annealing in hydrogen atmosphere in some situations for further applications. Crystallographic and morphology analyses of the nanomagnets were made by in-situ reflection high-energy electron diffraction (RHEED), ex-situ X-ray diffraction (XRD), transmission electron microscope (TEM). and atomic force microscopy (AFM). Magnetic properties were characterized by superconducting quantum interference device (SQUID) magnetometer and magnetic force microscopy (MFM). Further experimentals are conducted for magneto-optical characterizations for above mentioned metal and/or oxide nanomagnet arrays.
Magneto-transport Properties of Cobalt doped Indium Oxide Dilute Magnetic Semiconductors
Authors: Mamidi N. , Gupta R. K. , Ghosh K. , Mishra S. R. , Kahol P. K.
Published: April 2011

Recently, oxide-based dilute magnetic semiconductors (DMS) have attracted an immense research interest to the scientists due to the possibility of inducing room temperature ferromagnetism and potential uses in novel spintronic devices. In2O3, a transparent opto-electronic material, is an interesting prospect for spintronics due to its unique combination of magnetic, electrical, and optical properties. High quality thin films of Co-doped In2O3 DMS were grown on quartz substrates using pulsed laser deposition technique. All the films have been characterized using different techniques such as x-ray diffraction, Raman spectroscopy, optical transmission spectroscopy, electrical resistivity, and Hall Effect measurement. The effect of growth temperature and oxygen pressure on the electrical, magnetic, and optical properties of these films have been studied in detail. The optical transparency in all the films is high. It has been observed that the optical transparency depends on growth temperature and oxygen pressure. The electrical parameters such as resistivity, carrier concentration, and mobility strongly depend on both oxygen pressure and growth temperature. The films grown at low temperature are semiconducting in nature while the films grown at high temperature are metallic. Detailed temperature and magnetic field dependent resistivity, magnetoresistance, and Hall effect data will be presented. This work is supported by Research Corporation (award number CC6166).
High Quality Deposition of Strontium Titanate (STO) Thin Films using Sol-Gel Method
Authors: Uchiyama Kiyoshi , Fukunaga Daiki , Shiosaki Tadashi
Published: April 2011

Highly oriented strontium titanate (STO) thin films were successfully deposited on sapphire substrates using a sol-gel method. Sintering temperature of 1400°C and the use of c-cut sapphire for the substrates are the keys to obtain highly oriented thin films. The sample obtained on c-cut sapphire with a sintering temperature of 1400°C showed quite high (111)-orientation and a narrow full width half maximum (FWHM) value of 0.265°, which indicates a high quality deposition of the STO thin films.

We believe this high quality STO deposition technique will bring a new scope of oxide material applications for future electronic devices.
Role of SrTiO3 Seed Layer on Low-temperature Crystallization of Pb(Zr, Ti)O3 Films Prepared by Metalorganic Chemical Vapor Deposition
Authors: Moon Ji-Won , Wakiya Naoki , Kiguchi Takanori , Yoshioka Tomohiko , Junzo Tanaka , Shinozaki Kazuo
Published: April 2011

Role of SrTiO3 seed layer on low-temperature crystallization of Pb(Zr, Ti)O3 (PZT) film was investigated. The SrTiO3 seeds were prepared by pulsed laser deposition (PLD) with the temperature range of 400-600 °C and PZT films were prepared by thermal MOCVD. The pyrochlore free PZT films can be successfully crystallized at around 340 °C on SrTiO3 seed layers by thermal MOCVD. It was found that the role of SrTiO3 seed layer is not only pyrochlore suppression but also perovskite promotion. It is also considered that crystallinity, surface coverage and seed layer thickness are important parameters for low-temperature crystallization and electrical properties of PZT films.
Ozone Gas Generator Using Uniaxially Polarized LiTaO3 Single Crystal
Authors: Yoshikazu Nakanishi , Ide Junko , Kondo Jun , Fukao Shinji , Handa Katsumi , Tochio Tatsunori , Ito Yoshiaki , Tanaka Akikazu , Yoshikado Shinzo
Published: April 2011

The phenomenon that a ferroelectrics crystal carries out intrinsic polarization by the temperature change generally is known. The Ozone gas generation was investigated due to a strong electric field of this crystal under atmospheric pressure . When we added a rapid temperature change to the crystal, the charge non–equilibrium occurs around the crystal. Oxygen is influenced due to the non-equilibrium in charge and ozone is considered to be generated. Therefore, we used the high electric field induced due to the polarization of a ferroelectrics crystal in order to produce the ozone under atmospheric pressure.

As a result, we were able to produce ozone of the density of 400ppb in a oxygen gas flow of 1.5 liters per minute using this simple system: The crystals (Yamaju Co. Ltd. and Sumitomo metal mining Co. Ltd.) are used in thickness of 3, 5, 7, 10, 20, and 30 mm with a diameter of 4 inches, respectively. They are poled crystals.

Experiments on the maximum temperature (300 degree), the temperature gradient (100 degree/10 minite), and substrate materials(Cu and Al), the thickness of the crystal, and z face etc. were carried out during the temperature of LiTaO3 single crystal from 20C to about 300C. It is found that the amount of the ozone production increases rapidly, when the maximum temperature of LiTaO3 single crystal is raised and have a relation with the thickness of the crystal. However, the amount of the ozone production doesn't closely related with the X-ray generation that we use the crystal for.

In the present study, when the thickness of the crystal became large, polarization voltage became high, but generated efficiency of ozone was not necessarily proportional to thickness.
FERROELECTRIC THIN FILM SYSTEM IN PACKAGE DEVICES WITH INTEGRATED CAPACITORS OF 100 nF/mm2 & BREAKDOWN VOLTAGES OF 90 V
Authors: Klee Mareike , Keur Wilco , Mauczok Ruediger , Roest Aarnoud , Reimann Klaus , Peters Linda , Neumann Kai , Kiewitt Rainer
Published: April 2011

Thin film ferroelectric capacitors have been integrated with resistors and active functions such as ESD protection into small miniaturized modules, which enable a board space saving of up to 80%. With the optimum materials and processes, integrated capacitors with capacitance densities of up to 100 nF/mm2 and breakdown voltages of up to 90 V have been achieved. The integration of these high density capacitors with extremely high breakdown voltage is a revolution in the world of integrated passive components and has not yet been achieved in any other passive integration technology.
New method of reducing threading dislocation in epitaxial ZnO films grown on c-sapphire
Authors: Sun Yuekui , Cherns David
Published: April 2011

The behavior of threading dislocations (TDs) in ZnO/(0001)sapphire heterostructures grown by a two-step method have been investigated. The initial template, grown by pulsed laser deposition, consisted of a continuous underlayer, which was O-polar and an overlayer comprising a high density of Zn-polar nanorods. High densities (∼7×1010cm−2) of TDs were found to be restricted to the underlayer, whereas the nanorods were almost defect-free. Subsequent treatments by either hydrothermal growth or chemical vapour deposition (CVD) achieved epitaxial lateral overgrowth of nanorods and led to continuous Zn-polar films. The low TD density of nanorods remained until misoriented grain boundaries and boundary dislocations were generated when neighbouring nanorods become coalesced. The lateral migration of TDs in the overgrowth led to dislocation interactions and reduction of TDs. The total TD density at the top of the overlayer was estimated to be ∼1×109cm−2for hydrothermal growth and ∼7×109cm−2for CVD growth.
Visible Luminescence of Rare Earth Ions Doped Amorphous Zinc Oxide Thin Films Grown by Sputtering Technique
Authors: Jadwisienczak Wojciech M. , Vemuru Ajay S. , Khan Saima , Khan Aurangzeb , Kordesch Marty E.
Published: April 2011

We report on the luminescence of rare earth (RE) (Sm, Er, Tm) ions doped ZnO films grown by the rf-magnetron sputtering technique. Samples were insitu doped with Sm ion or with Sm, Er, and Tm ions simultaneously without any intentional co-dopants and deposited on c-Si or quartz substrates at low temperatures. Selected ZnO:RE samples were thermally annealed in 200ºC-1000ºC temperature range in oxygen or argon gas at ambient pressure. As-grown and annealed samples were amorphous (a-ZnO) as was confirmed by the X-ray analysis. Furthermore, a-ZnO:RE samples were investigated by energy diffraction, photoluminescence and cathodoluminescence. In general, CL spectra of as-grown RE-doped a-ZnO films show characteristic emission lines due to 4f-shell transitions of RE3+ ions. Optical excitation of as-grown a-ZnO doped with RE ions using above the bandgap excitation resulted in strong host emission overlapped with weak RE3+ emission bands. It was observed that a thermal annealing process promotes changes of RE ions' environments resulting in significant 4f-shell transition luminescence intensity quenching.
Performance of ZnO TFTs with AlN as Insulator
Authors: De Souza Maria Merlyne , Cross Richard B , Jejurikar Suhas , Adhi K P
Published: April 2011

The performance of ZnO TFTs fabricated via RF sputtering, with Aluminium Nitride (AlN) as the underlying insulator are reported. The surface roughness of ZnO with AlN is lower than that with SiN by at least 5 times, and that with SiO2 by 30 times. The resulting mobility for the three insulators AlN, SiN, SiO2 using identical process is found to be 3, 0.2-0.7 and 0.1-0.25 cm2/Vs respectively. There does not appear to be any corresponding improvement in the stability of the AlN devices. The devices demonstrate significant positive threshold voltage shift with positive gate bias and negative threshold voltage shift with negative gate bias. The underlying cause is surmised to be ultra-fast interface states in combination with bulk traps in the ZnO.
Crystallization of yttrium-iron garnet (YIG) in thin films: Nucleation and growth aspects
Authors: Zaezjev Michael V. , Chandra Sekhar Manda , Ferrera Marcello , Razzari Luca , Holmes Barry M , Sorel Marc , Hutchings David C , Pignolet Alain , Morandotti Roberto
Published: April 2011

We have studied the crystallization of the yttrium - iron garnet (Y3Fe5O12, YIG) polycrystalline phase in thin films fabricated by means of pulsed laser deposition . Films were deposited on MgO substrates in vacuum, in argon, and in oxygen. A subsequent post-deposition heat treatment (annealing) was done at 800°C in air. We have shown that the crystallization of YIG was precluded by co-existent parasitic phases present in the as-deposited films. Specifically, the growth of the parasitic phase needs to be suppressed in order to get a single-phase polycrystalline YIG. Lowering the substrate temperature has been shown to be a simple and efficient way to suppress the growth of parasitic phase and to obtain good quality YIG films after thermal treatment. This procedure has been demonstrated to be successful even when the YIG films were grown in vacuum and their composition was significantly out of stoichiometry.
Enabling the Desktop NanoFab with DPN® Pen and Ink Delivery Systems
Authors: Fragala Joseph S. , Shile R. Roger , Haaheim Jason
Published: April 2011

Depositing a wide range of materials as nanoscale features onto diverse surfaces with nanometer registration and resolution are challenging requirements for any nanoscale processing system. Dip Pen Nanolithography® (DPN®), a high resolution, scanning probe-based direct-write technology, has emerged as a promising solution for these requirements. Many different materials can be deposited directly using DPN, including alkane thiols, metal salts and nanoparticles, metal oxides, polymers, DNA, and proteins. Indirect deposition allows the creation of many interesting nanostructures. For instance, using MHA may be used to create arrays of antibodies, which then bond specifically to antigens on the surface of viruses or cells, to create cell or virus arrays. The DPN system is designed to allow registration to existing features on a writing substrate via optical alignment or nanoscale alignment using the core AFM platform. This allows, for instance, the nanoscale deposition of sensor materials directly onto monolithic electronic chips with both sensing and circuit features.

To enable the DPN process, novel pen and ink delivery systems have been designed and fabricated using MEMS technology. These MEMS devices bridge the gap between the macro world (instrument) and the nano world (nanoscale patterns). The initial MEMS devices were simple and robust both in design and fabrication to get products into the marketplace quickly. The first MEMS-based DPN device was a passive pen array based on silicon nitride AFM probe technology from Cal Quate's group at Stanford. The next two devices (an inkwell chip and a thermal bimorph active pen) were more complicated and took considerable effort to commercialize. In this work, some of the difficulties in bringing brand new MEMS devices from the prototype stage into production will be shared. The subsequent MEMS products have become even more complicated both in design and fabrication, but the development process has improved as well. For example, the 2D nanoPrintArray has 55,000 pens in one square centimeter for high throughput writing over large areas. The 2D arrays enable templated self assembly of nanostructures giving researchers the ability to control the placement of self assembled features rather than allowing the self assembly to occur randomly.

Applications of DPN technology vary from deposition of DNA or proteins in nanoarrays for disease detection or drug discovery, to deposition of Sol-gel metal oxides for gas sensors, and to additive repair of advanced phase-shifting photomasks.
Organic Semiconductors for Detection of Ionizing Radiation
Authors: Wilson Tiffany M.S. , Chinn Douglas A. , King Michael J. , Doty F. Patrick
Published: April 2011

Organic semiconductors are increasingly common in electronics and sensors, and are now under investigation for a novel type of radiation sensors at Sandia National Laboratories. This class of materials can offer wide band gaps, high resistivities, low dielectric constants, and high dielectric strengths, suggesting they may be suitable for solid-state particle counting detectors. A range of solution cast materials have been evaluated for this application, primarily in the family of poly(p-phenylene vinylene)s, or PPVs. The high ratio of hydrogen to carbon offers neutron sensitivity, while the low Z material provides some natural gamma discrimination. Compared to existing detectors, these materials could potentially offer large-scale radiation detection at a substantially reduced cost.

While PPVs hold promise for radiation detection, the mechanical and electrical properties must be optimized and the processing effects understood. Polymers can offer significantly simplified processing compared to the more common crystals used in solid state detection, which can be size limited and fragile. However, organic semiconductors are very sensitive to processing conditions, and mobility can be affected by orders of magnitude by processing variables, without altering any chemistry. Additives can also have dramatic effects on both electrical and mechanical properties. We report on nanoparticle additives that cause an increase in photoresponse of approximately three orders of magnitude as compared to a polymer film without additives. We separately show an order of magnitude increase in photoresponse by exposing the polymer/fullerene composite to sub-bandgap light.

Future work will analyze the feasibility of single particle detection and various geometries for optimization. Additional processing variables will also be investigated for further improvement of mobility and reduction of trap density.
Lutetium Oxide Coatings by PVD
Authors: Topping Stephen G , Park C H , Rangan S K , Sarin V K
Published: April 2011

Due to its high density and cubic structure, Lutetium oxide (Lu2O3) has been extensively researched for scintillating applications. Present manufacturing methods, such as hot pressing and sintering, do not provide adequate resolution due to light scattering of polycrystalline materials. Vapor deposition has been investigated as an alternative manufacturing method. Lutetium oxide transparent optical coatings by magnetron sputtering offer a means of tailoring the coating for optimum scintillation and resolution. Low crystallization in the sputtering process adversely affects transparency and scintillation, and is critical in growing stress free, thick coatings. The effect of process parameters on the crystallization is being investigated via x-ray diffraction (XRD), scanning electron microscopy (SEM) and emission spectroscopy and will be presented and discussed.
Chemical Modification of Carbon Materials with Sulfur Functionalities
Authors: Nakamura Takako , Ohana Tsuguyori
Published: April 2011

Photolysis of cyclic disulfides in the presence of carbon materials such as diamond films and single-walled carbon nanotubes led to a surface modification to introduce thioalkylthiol functional groups, confirming by means of Raman, X-ray photoelectron spectroscopy and mass spectrometer measurements. The results on the value of S/C ratio of sulfur-modified diamond films depends on irradiation time by monitoring with XPS. Through thioalkylthiol moieties, an attachment of gold nanoparticles using self-assembly process was performed on carbon materials surfaces.
Multi-wavelength Raman Spectroscopy of Nanodiamond Particles
Authors: May Paul William , Overton Philip , Smith James A , Rosser Keith N
Published: April 2011

We have used Raman spectroscopy with 3 different laser excitation wavelengths (near infrared: 785 nm, green 514 nm, and ultraviolet 325 nm) to study diamond particles as a function of particle size, ranging from 5 nm to 100's of μm. We find that the position of the 1332 cm−1 diamond line varies with particle size as a direct result of heating by the laser. This effect is more significant for lower wavelengths, probably as a result of the increased absorbance by nanodiamond particles in the UV.
The Influence of Different Surface Terminations on Electrical Transport and Emission Properties for Freestanding Single Crystalline (100) CVD Diamond Samples
Authors: Deferme Wim , Bogdan Andrey , Haenen Ken , De Ceuninck Ward , Flipse Kees , Nesladek Milos
Published: April 2011

The surface density of states of hydrogen and oxygen terminated diamond is an important parameter from the point of view of electrical transport properties at the surface. In addition, the presence of surface states has a detrimental influence on the electrical contact properties. Therefore it is of great importance that the influence of different species on the surface-related properties of the diamond layer is well understood.

In this work (100)-oriented CVD diamond films are terminated using hydrogen plasma with and without small additions of oxygen (1 to 4%). XPS and UPS measurements are performed to look at the influence of this addition on the surface band gap of the diamond samples. Using the TOF (Time-of-Flight) technique a comparison is made between oxidised and differently hydrogenated diamond surfaces. The results clearly show that the different terminations of the diamond surface have an influence on the electrical transport properties. For the oxidised surface, it is found that defect states are created in the surface band gap, increasing trapping. Contrary to this, fully hydrogenated layers behave differently suggesting that the surface DOS is significantly reduced. This fact can be confirmed when applying an electric field on the CVD diamond samples sandwiched between two metallic electrical contacts. In case of a metal deposited on a hydrogen terminated surface we can see a clear UV light emission, related to free exciton recombination in the contact-diamond-junction region. When the surface is oxidised the UV emission is damped, an effect which is attributed to the parallel recombination channels via the surface states.
Boron Doping of Microcrystalline and Nanocrystalline Diamond Films: Where is the Boron Going?
Authors: May Paul William , Ludlow William J , Hannaway Matthew , Smith James A , Rosser Keith N , Heard Peter J
Published: April 2011

We present data showing how the electrical conductivity and Raman spectra of boron doped ‘cauliflower’-type nanocrystalline (c-NCD) CVD diamond films vary as a function of B content. The conductivity is roughly linear as a function of B content between an onset threshold of ∼5×1020 cm−3 up to ∼6×1021 cm−3, with the higher concentrations giving near metallic conductivity values. The onset threshold may be due to compensating donors due to the large number of impurities and defects in these films. The position of the Lorentzian contribution to the 500 cm−1 Raman feature was used to estimate the B content and compared to the value measured using SIMS. We found that the Raman method overestimated the concentration of B by a factor of ∼5 for these c-NCD films. The shortfall may be explained if only a small fraction of the B found in the small-grained films is being incorporated into substitutional sites. We conclude that in diamond films with a high concentration of grain boundaries, the majority of the B (80% in some cases) must be present at or in the grain boundaries.
Reduction of Environmental Impacts in Crystalline Silicon Photovoltaic Technology: An Analysis of Driving Forces and Opportunities
Authors: Alsema Erik , de Wild-Scholten Mariska
Published: April 2011

We give an overview of historical developments with respect to the price and the Energy Pay-Back Time of crystalline silicon photovoltaic modules. We investigate the drivers behind both developments and observe that there is a large overlap between them. Reduction of silicon consumption, improved cell efficiency and the production technology for solar grade silicon have been identified as major drivers for both cost and impact reductions in the past. Also we look into future prospects for reduction of environmental impacts. It is estimated that developments underway to reduce costs will also result in a reduction of the Energy Pay-Back Time of a PV installation (in South-Europe) from 1.5-2.0 year presently to well below 1 year.
Ir based photovoltaic array performance assessment
Authors: Moropoulou Antonia , Palyvos J. A. , Karoglou M. , Panagopoulos V.
Published: April 2011

In this work infrared thermography was used as a diagnostic tool for the performance assessment of a photovoltaic array integrated on the southern façade of NTUA's Chemical Engineering Building. This grid-connected 50 kWp solar photovoltaic array, installed under an EC Thermie Project (SE-142-97-GR-ES), operates in a standard and hybrid PV-Thermal configuration, meant to save conventional energy. The thermographic system used for the analysis covers the 8-12 ìm of wavelength region. The thermal images obtained showed that there are temperature differences on the PV panels, which may be attributed to PV material defects, manufacturing faults, external abuse, or PV malfunction.
Integration of Land Use Aspects into Life Cycle Assessment at the Example of Biofuels
Authors: Held Michael , Bos Ulrike
Published: April 2011

It is well known that the transport sector causes significant environmental impacts worldwide and as a consequence influences the results of Life Cycle Assessment (LCA) studies. Today's fuels are dominated by crude oil derived fuels. In Europe currently 98 % of the road transportation is based on such crude oil derived fuels. Similar ratios can be observed e.g. in the US and other countries. In addition to the environmental impacts, the high dependency on the imports of fossil fuels motivates most European countries to investigate in other than fossil fuel based transport systems. Therefore the European Commission presented an action plan including a strategy with the objective to substitute 20% of crude oil derived fuels by alternative fuel until 2020. To achieve these goals, actions to reduce the import dependency of fuels, the usage of non renewable (fossil) resources and the environmental burdens connected to the use of fuel / propulsion systems have to be addressed. Besides, the energy carrier mix has to be broadened. Especially alternative fuels from renewable resources, BtL (Biomass to Liquid) are supposed to have a high potential.

Recent developments show, that there is a variety of options for fuels available as well as for propulsion technologies that utilize fuels based on renewable resources. It is therefore of key importance to select and promote the fuel/ propulsion system technology which is most beneficiary for a country or region from an environmental but also from an economic and social perspective. For such a sustainability evaluation it is essential to consider the local/regional boundary conditions such as availability of fuel resources, major pollution issues which need to be addressed, supply of secondary energy (e.g. power) etc. LCA is therefore a suitable approach to evaluate and compare different options, due to its transparent consideration of all life cycle stages.

Besides the environmental impacts and resource consumption which are addressed in LCA considerations the needed land is another important aspect when talking about biomass as a resource. As land is a scarce resource that is used for all industry sectors there is a need to address this issue also in LCA. Up to now, no commonly agreed upon methods exist which allow the integration of land use aspects in a consistent way into LCA Software and Database. Currently at LBP-GaBi, University of Stuttgart together with PE International, a method is developed to integrate land use aspects into LCA. Backward processes are now implemented in an applicable way into a LCA database system.

This Paper describes the main approach of the developed methodology for land use consideration within LCA.
Composition Dependence of Electrical Resistivity of Magnesium-cobalt Films During Hydridation and Dehydridation
Authors: Chan Yiu Bun , Ong Chung Wo
Published: April 2011

Palladium (Pd)-coated magnesium-cobalt (Mg-Co) films were prepared by co-sputtering at various ratios of the sputtering power of Mg to that of Co (PMg/PCo). The elemental composition of the films varies coherently with PMg/PCo. Films of higher Mg contents are of stronger interest. Their structures are more disordered even when just a relatively small amount of Co is added. The respective elemental contents are not uniform along depth, but more Mg aggregate near the surface region. A substantial volume fraction of Mg oxide is present. Though of structural complications, a Mg-rich film shows stronger and faster resistivity (ρ) response when reacting with hydrogen. Soaking an as-deposited Mg-rich film in 15% H2 (in argon) gives a huge change of ρ by 40 times, but it is mainly due to some irreversible structural change when a freshly prepared sample is first brought into contact with H2. The change of ρ in subsequent hydridation-dehydridation cycles is about 50%, while the drift of the baseline is less severe. Co-rich films give much weaker resistivity response to H2.
Preparation of Nitride Fuel by Spark Plasma Sintering Technique
Authors: Muta Hiroaki , Kurosaki Ken , Uno Masayoshi , Yamanaka Shinsuke
Published: April 2011

SPS technique was applied for fabrication of UN pellets. The dense sample was obtained with relatively low sintering temperature without any milling process and sintering additive, indicating that the SPS technique is suitable for fabrication of nitride fuel. The thermal conductivity and Young's modulus in axial direction were higher than those of reported values. EBSP analysis and electronic calculation supposed that weak grain orientation in [100] direction of the sample lead to these higher values.
Large thermoelectric power generated by the van Hove singularity in NaxCoO2
Authors: Takeuchi Tsunehiro , Kuno Syuhei
Published: April 2011

Mechanism leading to the large thermoelectric power and metallic electrical conduction observed in NaxCoO2 was investigated by means of angle resolved photoemission spectroscopy and the Bloch-Boltzmann theory. As a result of thermoelectric power calculation using the experimentally determined electronic structure under the assumptions of rigid band and constant mean free path, NaxCoO2 were found to possess the Boltzmann-type electrical conduction over a wide carrier-concentration range. Analysis using the simplest tight-binding bands revealed that the two-dimensional hexagonal lattices including the crystalline structure of the present NaxCoO2 produce a characteristic spectral conductivity leading to the large thermoelectric power and metallic electrical conduction.
Mechanical Alloying Synthesis of K2Bi8Se13– type Solid Solutions
Authors: Toumpas Nikolaos , Kyratsi Theodora , Hatzikraniotis Euripides , Tsiappos Andreas , Pavlidou Eleni , Paraskevopoulos Konstantinos M. , Chung Duck Young , Kanatzidis Mercouri G.
Published: April 2011

Solid solutions of β-K2Bi8-xSbxSe13are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. In this work, we aimed to synthesize solid solutions of β-K2Bi8-xSbxSe13type materials using powder techniques. The synthesis was based on mechanical alloying as well as sintering procedures. The products were studied in terms of structural features, composition and purity with powder x-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Preliminary results on thermoelectric properties as well as IR reflectivity measurements are presented.
Structural Studies of GeTe-AgSbTe2 Alloys
Authors: Thompson Alan , Sharp Jeff , Rawn C.J , Chackoumakos B.C.
Published: April 2011

GeTe, a small bandgap semiconductor that has native p-type defects due to Ge vacancies, is an important constituent in the thermoelectric material known as “TAGS” [1]. TAGS is an acronym for alloys of GeTe with AgSbTe2, and compositions are normally designated as TAGS-x, where x is the fraction of GeTe. TAGS-85 is the most important with regard to applications, and there also is commercial interest in TAGS-80. The crystal structure of GeTe1+δ has a composition-dependent phase transformation at a temperature ranging from 430°C (δ = 0) to ∼ 400°C (δ = 0.02) [2]. The high temperature form is cubic. The low temperature form is rhombohedral for δ < 0.01, as is the case for good thermoelectric performance. Addition of AgSbTe2 shifts the phase transformation to lower temperatures, and one of the goals of this work is a systematic study of the dependence of transformation temperature on the parameter x. We present results on phase transformations and associated instabilities in TAGS compositions in the range of 70-85 at.% GeTe.
Mechanical Characterization of PbTe-based Thermoelectric Materials
Authors: Ren Fei , Hall Bradley D , Ni Jennifer E , Case Eldon D , Sootsman Joe , Kanatzidis Mercouri G , Lara-Curzio Edgar , Trejo Rosa M , Timm Edward J
Published: April 2011

PbTe-based thermoelectric (TE) materials exhibit promising thermoelectric properties and have potential applications in waste heat recovery from sources such as truck engines and shipboard engines. TE components designed for these applications will be subject to mechanical/thermal loading and vibration as a result from in-service conditions, including mechanical vibration, mechanical and/or thermal cycling, and thermal shock.

In the current study, we present and discuss the mechanical properties of several PbTe-based compositions with different dopants and processing methods, including n-type and p-type specimens fabricated both by casting and by powder processing. Room temperature hardness and Young's modulus are studied by Vickers indentation and nanoindentation while fracture strength is obtained by biaxial flexure testing. Temperature dependent Young's modulus, shear modulus, and Poisson's ratio are studied via resonant ultrasound spectroscopy (RUS).
Design and evaluation of n-type Si1-xGex as a thermoelectric-conversion material
Authors: Imai Tomohiro , Iida Tsutomu , Miyata Yuki , Itoh Takashi , Funashima Hiroki , Takanashi Yoshifumi , Hamada Noriaki
Published: April 2011

Si1-xGex alloys show the high power generating efficiency as a thermoelectric- conversion material. We evaluate the thermoelectric power of the n-type SiGe system on the basis of the first principles calculations. The electronic-band-structure calculation is performed using all-electron full-potential linearized augmented-plane-wave (FLAPW) method within the local density approximation (LDA). The Seebeck coefficient is analyzed by the Bloch-Boltzmann equation. We find that the ordered rhombohedral SiGe has high Seebeck coefficient in comparison with zincblende SiGe. The efficiency of the thermoelectric power in Si1-xGex is gained by the local atomic configuration rather than the Ge concentration.