bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Treated PDMS by UV-Vis Light for Microfluidic Device
Authors: Kano Seisuke , Matsumoto Sohei , Ichikawa Naoki 
Published: February 2009

AbstractHydrophobic property of PDMS surface was improved by the 400 W UV-Vis lamp light irradiation in the atmospheric condition for several ten minutes. As a result of this surface treatment, the surface became to hydrophilic character for one month long. This surface treatment technique applied to PDMS micro-fluidic device and verified valve-less switching. The UV-Vis light irradiated to PDMS micro fluidic pattern with partly covered by aluminum foil. Finally inlet and outlets were connected 0.5 mm diameter tubes. The syringe pumps injected the distilled water into the inlet of the PDMS micro channel at the flow rates of 0.5, 5.0, and 50 μl/min for the both width channel. As results of water injection water flowed only the UV-Vis treated channel at the flow rates of 0.5 and 5.0 μl/min. On the other hand, the water flowed for all channels at the flow rate of 50 μl/min. This result was observed from 5.0 μl/min flow again for both width devices which dried by air. These results were occurred by the difference of the flow conductance and wettability. The mechanism of this hyrophilicity of PDMS was reported to form Si-O in the surface by means of glassy surface. From the IR spectra, the Si-O-Si peak shifted to higher wave number for UV-Vis irradiated PDMS than the untreated PDMS comparing with the other IR peaks. This result showed that the Si-O-Si network bonding of PDMS changed to the O-Si-O bonding around the surface.
Metal Wafer Bonding for MEMS Applications
Authors: Dragoi Viorel , Mittendorfer Gerald , Murauer Franz , Cakmak Erkan , Pabo Eric 
Published: February 2009

AbstractMetal layers can be used as bonding layers at wafer-level in MEMS manufacturing processes for device assembly as well as just for electrical integration of different levels. One has to distinguish between two main types of processes: metal diffusion bonding and bonding with formation of an interface eutectic alloy layer or an intermetallic compound. The different process principles determine also the applications area for each. From electrical interconnections to wafer-level packaging (with emphasis on vacuum packaging) metal wafer bonding is a very important technology in MEMS manufacturing processes.
A Perturbation-Based Method for Extracting Elastic Properties during Spherical Indentation of an Elastic Film/Substrate Bilayer
Authors: Kim Jae Hun , Gouldstone Andrew , Korach Chad S. 
Published: February 2009

AbstractAccurate mechanical property measurement of films on substrates by instrumented indentation requires a solution describing the effective modulus of the film/substrate system. Here, a first-order elastic perturbation solution for spherical punch indentation on a film/substrate system is presented. Finite element method (FEM) simulations were conducted for comparison with the analytic solution. FEM results indicate that the new solution is valid for a practical range of modulus mismatch, especially for a stiff film on a compliant substrate.
Microfabrication of Si/SiO2–Spherical Shells as a Path to Sub-mm3 Autonomous Robotic Systems
Authors: Vasilyev Vladimir , Reid James R. , Webster Richard T. 
Published: February 2009

AbstractA process for forming thin (1-3 μm) stacks of Si/SiO2 or SiO2/Si/SiO2 layers into spherical shells 0.5-3.0 mm in diameter is demonstrated as the baseline for realizing sub-mm3 micro-robots. The fabrication process combines bulk and thin-film micromachining, design of novel masks, and multistage wet and dry etching to release the layers from the substrate. The released layers curl up, self assembling into a spherical shell. The radius of curvature of the released stack is a function of the type, thickness, and residual stresses in the layers. The diameter of the resulting shells is calculated using a mechanical model of the multi-layer stacks. This calculation is compared with measurements of fabricated spheres. The fabrication process is compatible with CMOS circuitry, and future work will focus on realizing spheres with embedded solar cell as a power source and a capacitor for energy storage, which will result in a functional micro-robot.
Effects of Laser Ablation on Growth of ZnO/ZnS/ZnO Multilayer Structured Nanorods by Chemical Vapor Deposition
Authors: Hirate Takashi , Koisikawa Hiroaki , Yugi Makoto , Kumada Takuya , Matsuzawa Yuki , Satoh Tomomasa 
Published: February 2009

ABSTRACTZnO is an attractive II-VI compound semiconductor material for various optoelectronic devices. Recently, growth of various nanostructures of ZnO such as nanorod, nanobelt, nanowall, etc. has been reported, and ZnO has been considered as a promising material for nanodevices. We have studied on fabrication of aligned ZnO nanorods by a low-pressure thermal chemical vapor deposition (CVD) method cooperated with laser ablation of Mn pellet. In this paper, we report on fabrication of ZnO/ZnS/ZnO multilayer structured nanorods and particularly on effects of laser ablation on the morphology of the nanorods intending to develop a new electroluminescent device including ZnO nanorods. The fabrication method of ZnO/ZnS/ZnO multilayer structured nanorods is almost same method used in our previous study. Metal Zn vapor and O2 gas or H2S are used as precursors to synthesize ZnO or ZnS, and N2 is used as carrier gas. A Mn pellet is placed near a Si(111) substrate in a deposition chamber and ablated by a pulsed Nd:YAG laser beam (wavelength =1.064 mm, pulse width = 8 ns, repetition frequency = 10 shots/sec). The pressure is 13.3 Pa and the temperature is 550 C. When ZnO is grown, O2 of 0.88 SCCM mass flow rate is used as a precursor. When ZnS is grown, on the other hand, H2S of 2.0 SCCM mass flow rate is used as a precursor. The growth time is 15 min for each layer. Firstly, ZnO nanorods are grown. Laser ablation of Mn is executed for initial 3 min and only CVD is performed for remaining 12 min. The vertically aligned ZnO nanorods with 100 nm diameter and 1500 nm height are grown. Secondly, ZnS nanorod is grown on the top surface of the first ZnO nanorods. In this process, the morphology is not so dependent on execution of laser ablation of Mn for initial 3 min in this growth process. Finally, ZnO layer is again grown on ZnS/ZnO nanorods described above. When the laser ablation of Mn for initial 3 min is not executed, many fine ZnO whiskers with long length are grown with random directions on the top surface and on the side surfaces of ZnS/ZnO nanorods. When the laser ablation of Mn for initial 3 min is executed, on the other side, a thick whisker is grown on top surface of ZnS/ZnO nanorods. The shape is not nanorod. The diameter is abruptly decreased and the tip is very sharp. The growth of ZnO whisker on the side surface of ZnS/ZnO nanorods is not almost observed. It is found that the laser ablation of Mn for initial 3 min in the third ZnO growth strongly influences the morphology of the third ZnO layer. We estimate that the Mn species that are ablated from a Mn pellet and reaches the surface of ZnS/ZnO nanorods change any quality of the surface of ZnS/ZnO nanorods. We are now studying of finding the growth conditions of the third ZnO layer with morphology of nanorod on ZnS/ZnO nanorods that is considered to be suitable for electroluminescent devices.
Electrofluidic Positioning of Biofunctionalized Nanowires
Authors: Morrow Thomas J. , Kim Jaekyun , Li Mingwei , Mayer Theresa S. , Keating Christine D. 
Published: February 2009

ABSTRACTWe functionalized nanowires with three different probe peptide nucleic acid (PNA) sequences, and assembled the three populations onto a lithographically patterned chip. Electrofluidic assembly enabled positioning each set of nanowires to span a different pair of guiding electrodes. Fluorescence imaging was used to probe whether the PNA on the individual nanowires remained able to selectively bind complementary DNA targets following assembly and integration of the positioned nanowires onto the chip surface.
Photodetector Using Surface-Plasmon Antenna for Optical Interconnect
Authors: Ohashi Keishi , Fujikata Junichi 
Published: February 2009

AbstractWe used a surface-plasmon antenna to obtain small photodetectors for LSI on-chip optical interconnection by using near-field light generated by the antenna. Such near-field devices are not constrained by the diffraction limit and they offer an approach to integrated nanoscale photonic devices. A small semiconductor structure is located near the antenna to absorb the near-field light. This structure can be made as small as the Schottky depletion layer, so the separation between electrodes can be reduced to almost the size of the near-field region. We have demonstrated a “Si nano-photodiode” or plasmon photodiode that uses the near-field localized in a subwavelength region, which is usually relatively large in size because of the long absorption length for Si (˜10 μm at a wavelength of ˜800 nm). The Si nano-photodiode has a fast impulse response with a full-width at half-maximum of ˜20 ps even when the bias voltage is small (˜1 V or less). We demonstrated an on-chip optical interconnect chip to operate circuitry in an LSI chip by using waveguide-coupled Si nano-photodiodes.
Photoluminescence from Ge/Si Nanocrystals Embedded in Silicon Oxide Matrix Annealed in Hydrogen Gas
Authors: Uekusa Shin-ichiro , Kosaka Naoki 
Published: February 2009

AbstractPhotoluminescence (PL) spectra from Si nanocrystals embedded in silicon oxide matrix (Si-SiO2) thin films, Ge embedded in silicon oxide matrix (Ge-SiO2) thin films and both Ge and Si embedded in silicon oxide matrix (Ge/Si-SiO2) thin films prepared by RF magnetron sputtering were investigated. All as-deposited thin films were annealed for 1h in the temperature range from 500°C to 1100°C in Ar or H2 atmosphere. The PL spectra of Si-SiO2 thin films exhibited red luminescence at an annealing temperature of 1100°C and the PL intensity of the sample annealed in H2 gas increased by a factor of approximately 6.3 in comparison with sample annealed in Ar gas. Subsequently, The PL intensity of main peak centered at about 400 nm (V-band) of Ge-SiO2 thin films annealed in H2 gas exhibited strong comparison with the sample annealed in Ar gas. Finally, the PL spectra of Ge/Si-SiO2 thin films exhibited strong peak centered at approximately 500-530 nm (G-band) besides V-band and others in the temperature range from 700°C to 1000°C. The PL intensity of G-band of the samples annealed in H2 gas exhibited weak comparison with Ar gas.
Ab initio Computationally Generated Nanoporous Carbon and its Comparison to Experiment
Authors: Romero Cristina , Valladares Ariel A. , Valladares R. M. , Valladares Alexander , Calles Alipio G. 
Published: February 2009

AbstractNanoporous carbon is a widely studied material due to its potential applications in hydrogen storage or for filtering undesirable products. Most of the developments have been experimental although some simulation work has been carried out based on the use of graphene sheets and/or carbon chains and classical molecular dynamics. Here we present an application of our recently developed ab initio method [1] for the generation of group IV porous materials. The method consists in constructing a crystalline diamond supercell with 216 atoms of carbon and a density of 3.546 g/cm3, then lengthening the supercell edge to obtain a density of 1.38 g/cm3, yielding a porosity of 61.1 % in order to be able to compare with experimental results reported in the literature [2]. We then subject the resulting supercell to an ab initio molecular dynamics process at 1000 K during 295 steps. The radial distribution functions obtained are compared to experiment to discern coincidences and discrepancies.
Opto-Electronic Properties of Ge and Si Related Nanostructures on Ultrathin Si Oxide Covered Si Surfaces
Authors: Ichikawa Masakazu , Nakamura Yoshiaki , Shklyaev Alexander , Fujinoki Norohito 
Published: February 2009

AbstractWe present a method to form semiconductor nanodots on Si substrates by using ultrathin Si oxide technology and the results on their opto-electronic properties. We can form ultra-small semiconductor nanodots with the size of ˜5nm and ultra-high density of ˜1012 cm−2 on Si surfaces covered with ultrathin SiO2 films of ˜0.3nm thickness. We focus on the Ge and GeSn nanodots on Si substrates and those embedded in Si films. These structures exhibit quantum confinement effects and intense luminescence in the energy region of about 0.8 eV.
Design, Fabrication and Characterization of Si3N4 Photonic Crystal Nanocavities for Diamond-based Quantum Information Processing Applications
Authors: Khan Mughees , McCutcheon Murray W. , Babinec Thomas , Deotare Parag , Lončar Marko 
Published: February 2009

AbstractIn order to improve the efficiency of quantum emitters, in particular nitrogen-vacancy (NV) color centers in diamond nanocrystals (NCs), it is important to enhance their photon production rate as well as the collection efficiency of the emitted photons. This can be achieved by embedding the emitters within optical cavities. Here we describe the design and fabrication of 1-D photonic crystal nanocavities in an air-bridge silicon nitride (SiNx) structure. In spite of the low index of silicon nitride (n˜2), we were able to design optical nanocavities with Quality factors as high as Q˜1 × 106. These nanocavities were designed to operate near 637 nm in order to strongly enhance the zero-phonon line (ZPL) emission of an NV center in a diamond NC while suppressing the in-plane emission into the phonon side-band. Simulation results show that a NV center placed near the top of the cavity would experience a reduction of radiative lifetime from ˜15ns to ˜2ps (Purcell factor ˜7000), thus significantly improving the photon production rate. Experimental results show a cavity resonance at ˜630nm, with a linewidth corresponding to Q˜1250, limited by the spectrometer resolution. The presented work is an important step towards the realization of diamond-based single photon devices, including switches.
Si Single-Electron SOI-MOSFETs: Interplay with Individual Dopants and Photons
Authors: Tabe Michiharu , Burhanudin Zainal Arif , Nuryadi Ratno , Moraru Daniel , Ligowski Maciej , Jablonski Ryszard , Mizuno Takeshi 
Published: February 2009

AbstractWe have demonstrated that Si single-electron or single-hole SOI-MOSFETs with the multi-dots channel have attractive new functions such as photon detection and single-electron transfer. Multi-dots formed by selective-oxidation-induced patterning of the thin SOI layer have been used in the experiments of photon detection, while, most recently, we have utilized smaller dots consisting of individual dopant potentials in single electron transfer devices. Furthermore, in order to directly observe spatial landscape of single charges in the channel region, we have developed Low Temperature-Kelvin Probe Force Microscopy and succeeded in detecting single-dopant potential in the channel region. In this paper, photon detection by these devices will be primarily described.
In-situ electrical probing of zones of nanoindentation-induced phases of silicon
Authors: Ruffell Simon , Bradby Jodie , Williams Jim , Major Ryan , Warren Oden 
Published: February 2009

AbstractPhase transformed zones of silicon have been formed by nanoindentation both at the micro- and nanoscale and electrically probed using an in-situ measurement system. Zones composed of the high pressure crystalline phases (Si-III/Si-XII) have higher conductivity than those of amorphous silicon (a-Si). At the microscale probing laterally across the surface shows that the conductivity varies within the zones composed of the high pressure phases. The sensitivity to the different conductivities of the two phases allows mapping within the zones. Finally, at the nanoscale the conductivity of the high pressure phase zones can be correlated with the position of the pop-out associated with the formation of the phases. The zones have higher conductivity when the pop-out occurs earlier on unloading and we suggest that this is due to the reduction in trace volumes of a-Si formed during the early portion of the unloading cycle.
In situ XPS investigation about the growth of the first atomic layer of Ta(N) films deposited by thermal TBTDET ALD
Authors: Strehle Steffen , Schmidt Daniela , Gutsch Sebastian , Knaut Martin , Albert Matthias , Bartha Johann W. 
Published: February 2009

AbstractTa based films are important building blocks for modern microelectronic applications. To meet the requirements of miniaturization, atomic layer deposition appears to be an alternative technology in comparison to PVD and CVD. In the present paper investigations of a thermal TBTDET ALD process will be presented with emphasis to the first ALD reaction cycles on native silicon oxide and HF etched silicon surfaces. The investigations show that the substrate chemistry is a crucial parameter for the film growth and appears to be a key to control the ALD deposition. The investigations were done by XPS without any vacuum break between the deposition and the surface analysis.
Topochemical Modification of Layered Perovskites
Authors: Choi Jong-Lak , Josepha Elisha , Zhang Xiao , Wiley John 
Published: February 2009

AbstractTopochemical reaction strategies based on two-step intercalation methods are studied. Reactions involving reductive followed by oxidative intercalation are quite effective in making new compounds; the synthesis and characterization of (A2Cl)LaNb2O7 (A = Rb, Cs) are presented. An alternative synthetic route, oxidative followed by reductive intercalation, is also discussed.
Swelling of Layered Potassium Ruthenate into Nanosheet Crystallites
Authors: Fukuda Katsutoshi , Kato Hisato , Sugimoto Wataru , Takasu Yoshio 
Published: February 2009

AbstractThe swelling and exfoliation behaviors of layered potassium ruthenate and the resultant unilamellar crystallites of RuO2.10.2− with nanosheet morphology were studied. The reaction of layered H0.2RuO2.1·0.9H2O with tetrabutylammonium hydroxide (TBA+OH−) was found to be extremely sensitive to the interlayer water content. The use of highly hydrous layered protonic ruthenate was essential for obtaining direct exfoliation. The swelling behavior was also affected by the ratio of TBA+ to ion-exchangeable H+ in the layered compound. At low ratios of TBA+/H+≤1, the layered precursor scarcely exfoliated and mostly deposited as an intercalation compound. In the intermediate TBA+/H+ range, an auburn colloidal suspension containing exfoliated nanosheets was formed, while much larger ratios were less favorable for the exfoliation.
Spin, Orbital and Lattice Coupling in the Double Perovskite Ba2154SmMoO6
Authors: Mclaughlin Abbie 
Published: February 2009

AbstractAn unexpectedly high antiferromagnetic transition temperature (TN = 130 K) has been observed in the double perovskite Ba2154SmMoO6 as a result of a strong interplay between spin, orbital and lattice degrees of freedom. A variable temperature neutron diffraction study of Ba2154SmMoO6 demonstrates that the orbital order below TN is as a result of a Jahn-Teller distortion of the MoO6 octahedra.
Synthesis and Structures of Novel Lanthanide Benzenedicarboxylates
Authors: Gil-Mateo Paola , Wang Xiqu , Jacobson Allan 
Published: February 2009

AbstractThree novel lanthanum benzenedicarboxylates La2(BDC)3(H2O)4 (1), La4(BDC)3(OH)6 (2) and La3(BDC)2(OH)5 (3) (BDC = 1,4-benzenedicarboxylate) were synthesized by hydrothermal reactions and their structures determined from single crystal X-ray diffraction. All three compounds are 3D framework structures consisting of layers of LaOn polyhedra cross-linked by BDC ligands along the layer stacking direction. In 1 the layers contain separated [LaO6(H2O)2] polyhedra that are bridged by the carboxylate groups of the BDC anions. Compounds 2 and 3 both have highly condensed lanthanum oxide-hydroxide polyhedra. In 2 the layers are wavy and consist of [LaO5(OH)4] and [LaO4(OH)5] polyhedra that share common corners, edges, and faces. In 3, the layers are similar but comprise [LaO3(OH)5] and [LaO4(OH)5] polyhedra.
Synthesis of porous biomorphic Cu/CeO2/Al2O3by using cotton as templates
Authors: Chiu Ka Lok , Kwong Fung Luen , Jia Juncai , Li Jia , Ng Hang Leung 
Published: February 2009

AbstractMethanol has high volumetric energy density and is relatively easy to handle, thus methanol fuel cells have potential applications in automobiles and portable devices. There are two types of methanol fuel cells. The direct type cell oxidizes methanol for power generation while the indirect type first converts methanol to hydrogen and uses it as fuel. Indirect methanol fuel cell has several advantages. It has a higher efficiency compared to the direct type, and does not need hydrogen supply and storage as in the hydrogen fuel cell. However, its size is larger and it is heavier as reforming methanol and removing CO are required. Meanwhile, the catalyst with mechanical support such as ceramic foam or honeycomb accounts for a significant part of its total weight. Thus, its applications are limited, especially in portable devices. As a remedy, we have developed a high surface area/weight ratio, low cost and self-supported catalyst for the indirect methanol fuel cell by using porous biomorphic Cu/CeO2/Al2O3. This ternary system is produced via a chemical method by using cotton as templates. Cu/CeO2is a catalyst for reforming methanol and for oxidation of CO, and the Al2O3is to prevent segregation of the Cu and CeO2fine particles.To prepare this biomorphic Cu/CeO2/Al2O3, a 0.5 M Boehmite solution was prepared with C9H21O3Al via the Yoldas process. It was then mixed with 0.5 M Cu(NO3)2and 0.5 M Ce(NO3)3solutions. The weight percentage ratio of Cu:Ce:Al was 3:2:5 in the mixture. Cotton balls were soaked in the mixture, and they were air dried before sintered in air at temperatures ranged from 400°C to 800°C. The sintered samples were further reduced with diluted hydrogen at 250°C for 2 hours. The final products were characterized via SEM, TEM, XRD, BET, DTA and TGA.We found that the products maintained the original macroscopic shape and size of the cotton ball and no obvious shrinkage was observed. The SEM images showed that the original internal fibrous networks in the raw cotton was retained in the biomorphic product, however, the fibers became hollow. The XRD result confirmed that the Cu/CeO2/Al2O3compound was produced when the sintering temperatures between 500°C and 700°C. The sizes of the Cu and CeO2particles in the products were in nanometer scale. When the sintering temperature was higher than 700°C, CuAl2O4was produced. When temperature was below 500°C, Cu2O was produced. From the DTA and TGA results, the pyrolysis of soaked cotton occurred between 190°C and 380°C. The sample weight decreased to about 16% of its original at 380°C, and kept almost constant at higher temperatures. The BET area of our products was about 100m2per gram, which was comparable to those of similar products synthesized by other methods. Our products are self supported and mechanical support was not required. It is expected that the weight of catalysts can be greatly reduced and the energy utilization of the indirect methanol fuel cell can be improved.