bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epitaxial Oxide Thin-Film Phosphors for Low Voltage FED Applications
Authors: Lee Yong Eui , Norton David P. , Budai John D. , Rack Philip D. , Peterson Jeffrey , Potter Michael D. 
Published: April 2011

ABSTRACTEpitaxial ZnGa2O4 and Sr2CeO4 thin-film phosphors were successfully grown on (100) MgO, YSZ, and SrTiO3 single crystal substrates using pulsed laser ablation. Cathodoluminescence efficiency was remarkably enhanced by adding lithium in the ZnGa2O4 and ZnGa2O4:Mn for both blue and green light emitting thin-film phosphors. The highest efficiencies, in this experiment, were 0.35 and 0.29 lm/W at 1kV for as-deposited blue and green zinc gallate phosphor films, respectively. In case of Sr2CeO4 films, the highest luminescence was 0.14 lm/W at 1kV and 0.26 A/m2 for films annealed at 1000°C in air.
Intense Photoluminescence and Photoluminescence Enhancement upon Ultraviolet Irradiation in HYydrogenated Nanocrystalline Silicon Carbide
Authors: Yu M.B. , Rusli  , Yoon S.F. , Xu S.J. , Chew K. , Cui J. , Ahn J. , Zhang Q. 
Published: April 2011

ABSTRACTHydrogenated nanocrystalline silicon carbide (nc-SiC:H) films were deposited in an electron cyclotron resonance chemical vapor deposition (ECR-CVD) system using silane (SiH4) and methane (CH4) as source gases. It was discovered that under the deposition conditions of strong hydrogen dilution and high microwave power, nanocrystalline grains embedded in an amorphous matrix can be obtained, as confirmed by TEM study. Steady state and time-resolved photoluminescence (PL) from these films were investigated. The films exhibit intense visible PL at room temperature under laser excitation. The PL emission peaks at 2.64 eV, which is higher in energy compared to the bandgap of cubic SiC. Temporal evolution of the emission peak exhibits a double-exponential decay. Two distinct decay times of 179 ps and 2.88 ns were identified, which are at least 2 orders of magnitude faster than that of bound excition transitions in bulk 3C- SiC at low temperature. It was found that upon ultraviolet irradiation using an Ar+ laser (351nm) the PL intensity of the films was enhanced. After 20 minutes irradiation, the PL intensity increased by about three times. This result suggests that the UV light may lead to modification of nonradiative recombination centers in the films. These nc-SiC:H films are promising for application in large area flat panel displays and in optoelectronic storage technology.
Uniform, High Performance Poly-Si TFTs Fabricated by Laser- Crystallization of PECVD-Grown a-SI:H
Authors: Toet D. , Sigmon T.W. , Takehara T. , Tsai C.C. , Harshbarger W.R. 
Published: April 2011

ABSTRACTPolycrystalline silicon thin film transistors (TFTs) were fabricated using laser crystallization of thin amorphous Si films grown by plasma-enhanced chemical vapor deposition. The films were exposed to a scanned XeCl excimer laser beam at 350 mJ/cm2. At this fluence the Si film com- pletely melted and crystallized in the form of uniformly distributed grains with an average size of 39 nm. One of the films was then subjected to a low fluence laser scan (250 mJ/cm2), which re- sulted in the melting of the top part of the film and lead to an increase in grain size. The TFTs fabricated without the partial melt method had good electrical properties and uniformities. The partial melt method lead to substantial improvements in most device characteristics, while the uniformity remained good.
Top Gate Self-Aligned μc-Si TFTs using Layer-by-Layer Method and Ion-doping Method
Authors: Nakata Yukihiko , Murata Yasuaki , Hijikigawa Masaya 
Published: April 2011

ABSTRACTWe investigated the Layer-by-Layer method to obtain thin μc-Si films. Good quality μc-Si films can be obtained at a thickness of 600 Å Ion-doping of phosphor to i-type μc-Si was investigated to realize the top-gate, self-aligned μc-Si TFT. High conductivity, more than 1 ohm-cm, can be obtained. Using the combination of Layer-by-Layer deposition method and ion-doping method, we fabricated top gate self-aligned μc-Si TFTs. The mobility of TFTs with 600Å-thick μc-Si channel layer is 1.5 cm2/Vs, which is about three times that of a-Si TFT's mobility. The top gate self-aligned μc-Si TFT is very promising technology for large LCD with high mobility.
Space Based Applications for FEA Cathodes (FEAC)
Authors: Gilchrist B. E. , Michigan U. , Arbor Ann , Jensen K. L. , Gallimore A. D. , Michigan U. , Severns J. G. 
Published: April 2011

ABSTRACTCold cathodes such as field emitter arrays offer the potential to benefit or enable space-based applications of critical commercial, government, or military importance by providing an electron source that is low power, low cost, requires no consumables, potentially robust as well as highly reliable. Applications that would especially benefit from such cold cathodes include low power electric propulsion (EP) thruster technology, electrodyanamic tethers (ED) for propellantless propulsion in low-Earth orbit, and spacecraft negative potential charge control. In controlled environments, field emitter arrays have shown substantial capability, but have failed in harsher environments more typical of space applications. We argue that a combination of localized arc suppression coupled with a low work function, but nevertheless robust, coating such as zirconium carbide would provide the needed ruggedness to withstand energetic ions, oxygen fluxes, and adsorbates typical of a spacecraft environment. We have found that arc-protected and coated FEACs that can operate in a 1-10 microTorr pressure environment with current densities of less than 0.1 Amps/cm^2 and gate voltages between 50-100 Volts, would enable reliable, lowcost devices capable of operating in the required space environment.
A Concentric Circular Type in-situ Vacuum Sealed Lateral Feas Employing E-Beam Evaporator
Authors: Lim Moo-Sup , Han Min-Koo , Choi Yearn-Ik 
Published: April 2011

ABSTRACTIn this paper, we propose concentric circular lateral field emitter structure which is more sstable in fabricating and maintaining vacuum conditions. The new FEAs have concentric circular shape while our previous FEAs are stripe type. The anode is formed at inner circle and the cathode is outer circle respectively. We use Molybdenum or Silicon dioxide as a sealing material. After we fabricating tips, Molybdenum or Silicon dioxide is deposited with e-beam evaporator at base pressure of 3.5×10−6Torr. In this process, the micro-cavity remains vacuum cavity without filling Molybdenum or oxide due to step coverage of evaporation. It should be noted that the vacuum level of the micro-cavity can be identical to the base pressure of the e-gun evaporator chamber. All of the two types of new FEAs show good reproducibility in fabricating and maintaining vacuum conditions. Field emitter structure that the anode is located at inner circle shows superior field emission characteristics. The measurements of long term stability for the anode current show that oxide is the most promising material for in-situ vacuum sealing.
Micro-Structural and Field Emission Characteristics of Nitrogen-Doped And Micro-Patterned Diamond-Like Carbon Films Prepared by Pulsed Laser Deposition
Authors: Shin Ik Ho , Choi Jae Hyoung , Lee Jeong Yong , Lee Taek Dong 
Published: April 2011

ABSTRACTEffect of nitrogen doping on field emission characteristics of patterned Diamond-like Carbon (DLC) films was studied. The patterned DLC films were fabricated by the method reported previously[1]. Nitrogen-doping in DLC film was carried out by introducing N2 gas into the vacuum chamber during deposition. Higher emission current density of 0.3∼0.4 mA/cm2 was observed for the films with 6 at % N than the undoped films but the emission current density decreased with further increase of N contents. Some changes in CN bonding characteristics with increasing N contents were observed. The CN bonding characteristics which seem to affect the electron emission properties of these films were studied by Raman spectroscopy, x-ray photoemission spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The electrical resistivity and the optical band gap measurements showed consistence with the above analyses. High-resolution transmission electron microscopic (HRTEM) results also support the formation of graphite-like phase in 9 at % N-doped DLC film.
Colloidal Solution of Metal Nanoparticles as a Catalyst for Carbon Nanotube Growth
Authors: Ago Hiroki , Ohshima Satoshi , Komatsu Toshiki , Kuriki Yasunori , Yumura Motoo 
Published: April 2011

AbstractAligned multi-wall carbon nanotubes (MWNTs) were successfully grown on a Si substrate based on a thermal chemical vapor deposition (CVD) method. We employed Co metal nanoparticles as the catalyst for nanotube growth, which were prepared by a reverse micelle method. The reverse micelle method provides nanoparticles covered with surfactants so that they are dispersed in organic solvent and, thus highly processible. The present MWNT arrays are promising for application in field emission displays, because of much lower nanotube density compared with the previously reported arrays.
Purity and Solubility of Nanotubes in Arc Discharge Carbon Powder
Authors: Coleman Jonathan N. , Dalton Alan B. , McCarthy Brendan , Barklie Robert C. , Blau Werner J. 
Published: April 2011

AbstractWe have described a novel experimental technique to separate nanotubes from other unwanted carbon species in arc generated carbon soot. A conjugated polymer was used to bind to nanotubes in solution. The resultant hybrid was soluble while extraneous carbon material formed a sediment at the bottom of the sample bottle. This process was monitored using electron paramagnetic resonance (EPR) which showed that 63% of nanotubes were kept in solution while 98.1% of impurities were rejected. This allowed the calculation of the nanotube content in the carbon soot using EPR and thermo-gravitational analysis (TGA) yielding a purity value of 34% for the soot used in this study. This is compatible with estimates made using electron microscopy.
Quantum Transport Properties of Carbon Nanotubes in the Coulomb Blockade Regime
Authors: Mehrez H. , Guo Hong , Wang Jian , Roland Christopher 
Published: April 2011

AbstractRecent experimental measurements on transport through carbon nanotubes in the Colomb Blockade regime showedm at zero bias and zero magnetic field, an alternation in the Coulomb peak heights as electrons are added to the nanotube. This surprsing peak-height alternation is shown to be related to the odd/even parity of the number of electrons in sider the nanotube. We invesitiaged this phenmenon theoretically with a new many-body apporach. and find that the anomalous behaviour may be attributed to the spin degenerate states. We alos show that asymmetric current saturation as a function of bias voltage polarity, also observed experimentally, is due to eigenstate relaxtions within the nanotube.
Solubility of carbon nanotubes
Authors: Panhuis Marc In Het , Coleman Jonathan N. , Blau Werner J. 
Published: April 2011

AbstractWe have described a novel experimental technique to separate nanotubes from other unwanted carbon species in arc generated carbon soot. A conjugated polymer was used to bind to nanotubes in solution. The resultant hybrid was soluble while extraneous carbon material formed a sediment at the bottom of the sample bottle. This process was monitored using electron paramagnetic resonance (EPR) which showed that 63% of nanotubes were kept in solution while 98.1% of impurities were rejected. Optimal polymer characteristics for nanotube solubility were identified using geometry optimisation and experimental evidence. It was calculated that a successful polymer has a flat shaped helical backbone with solvent solubilising groups projected outwards. This is achieved with the following polymer characteristics, two solvent solubilising groups on a twist allowing π-conjugated backbone.
Polarized Raman Spectra of Carbon Nanotubes
Authors: Jorio Ado , Brown Sandra D.M , Dresselhaus Gene , Dresselhaus Mildred S. , Pimentap Marcos A. , Saito Riichiro , Rao Apparao M. , Kneipp Katrin 
Published: April 2011

AbstractP olarizedresonant Raman spectra for the G-band were obtained from a rope of aligned semiconducting SWNTs and from nonaligned semiconducting and metallic SWNTs. Based on group theory analysis and related theoretical predictions, we assign the symmetry for the modes in the G-band of both metallic and semiconducting SWNTs. he frequency shifts of the tangential G modes from the 2D graphite-like E2g2 frequency are discussed in terms of the nanotube geometry.
High Resolution Resists for Next Generation Lithography: The Nanocomposite Approach
Authors: Gonsalves Kenneth E. , Wu Hengpeng , Hu Yongqi , Merhari Lhadi 
Published: April 2011

AbstractThe SIA roadmap predicts mass production of sub-100 nm resolution circuits by 2006. This not only imposes major constraints on next generation lithographic tools but also requires that new resists capable of accommodating such a high resolution be synthesized and developed concurrently. Except for ion beam lithography, DUV, X-ray, and in particular electron beam lithography suffer significantly from proximity effects, leading to severe degradation of resolution in classical resists. We report a new class of resists based on organic/inorganic nanocomposites having a structure that reduces the proximity effects. Synthetic routes are described for a ZEP520®nano-SiO2 resist where 47nm wide lines have been written with a 40 nm diameter, 20 keV electron beam at no sensitivity cost. Other resist systems based on polyhedral oligosilsesquioxane copolymerized with MMA, TBMA, MMA and a proprietary PAG are also presented. These nanocomposite resists suitable for DUV and electron beam lithography show enhancement in both contrast and RIE resistance in oxygen. Tentative mechanisms responsible for proximity effect reduction are also discussed.
Fabrication of Micro- and Nanostructures with Monodispersed Colloidal Spheres as the Active Components
Authors: Gates Byron , Mayers Brian , Li Zhi-Yuan , Xia Younan 
Published: April 2011

AbstractMonodispersed colloidal spheres with dimensions in the range of 100 nm to 10 μm can be used as building blocks to fabricate highly ordered 3D micro- and nanostructures. For example, they can be self-assembled into closely packed lattices, which can be subsequently used as templates to generate 3D porous structures. Here we present the recent progress in our group regarding this approach.
Precise Characterization of Resists and Thin Gate Dielectrics in the VUV Range for 157nm Lithography
Authors: Boher Pierre , Evrard Patrick , Piel Jean Philippe , Defranoux Christophe , Stehlé Jean Louis 
Published: April 2011

AbstractSpectroscopic ellipsometry is one of the most important tools for thin film metrology. It is now intensively used in microelectronics and especially for the microlithographic applications. Instrumentation for the next generation of VUV lithography at 157nm requires special optical setup since oxygen and water are extremely absorbing below 190nm. Recently a new ellipsometer included in a purged glove box to reduce the oxygen and water contamination in the part per million range has been developed. In the VUV range, roughness and interface diffusion become critical since the layer thickness is generally reduced. An independent characterization technique like the grazing x-ray reflectance is then extremely complementary to ellipsometry in this wavelength region. The present paper presents recent results on up to date lithography samples combining the two characterization techniques. Photoresists and gate dielectrics are successively examined.
Nanolithography by Electron Beam Resist-trimming Technique
Authors: Maeda Tatsuro , Ishii Kenichi , Suzuki Eiichi , Hiroshima Hiroshi , Iida Tsutomu , Takanashi Yoshihumi , Ahmet Parhat , Chikyow Toyohiro , Taguchi Hirohisa 
Published: April 2011

AbstractWe have investigated a resist-trimming process for SAL601 chemically amplified negative electron beam resist. Ultra-fine SAL601 resist patterns with a width of 16nm were obtained by an isotropic trimming process in oxygen plasma. This pattern resolution in SAL601 could not be obtained through direct electron beam lithography alone. Using the trimmed electron beam resists, we have successfully fabricated ultra-fine poly-silicon patterns of less than 20nm width. We applied this nanolithography technique to fabricating an ultra-small metal-oxide-semiconductor field-effect-transistor (MOSFET) and revealed that this trimming process is a useful method for nanometer-scale silicon device fabrication.
Fabrication of Helically Perforated Thin Films
Authors: Harris K.D. , Westra K.L. , Brett M.J. 
Published: April 2011

AbstractUsing glancing angle deposition and templating techniques, we have fabricated a number of unique thin film microstructures. Engineered columnar thin films having the inverse of the desired structure (i.e., arrays of helices or chevrons) were first deposited by glancing angle deposition. These films were then filled with a solution of the desired material, and allowed to cure. The template material was then removed by chemical etching, leaving a perforated thin film. Such films have been produced of photoresist and spin-on-glass, on both silicon and glass substrates. The perforations have taken the form of chevrons and helices of large and small pitch, and have been arranged in both random and periodic (1μm spacing) arrays.
Fabrication of Photonic Crystals Using Metal Clusters as Nuclei for Self-formation of Etching Masks
Authors: Tada Tetsuya , Poborchii Vladimir V. , Kanayama Toshihiko 
Published: April 2011

AbstractWe developed a fabrication process of regular arrays of Si nanopillars using self-formation of etching masks with metal clusters as formation nuclei. When Si substrates deposited with metal clusters are subjected to electron cyclotron plasma etching with SF6 at around -130 °C, reaction products in the plasma, SxFy, condense preferentially at the clusters, leading to the self-formation of nanoscale etching masks. As a result, Si pillars, about 10 nm in diameter and 100 nm tall, are formed with remarkably narrow size-distributions when Au clusters of 1-3 nm diameter are used. This method can be easily combined with electron beam lithography technique, which enables us to define pillar positions. Using this process, we have fabricated 2 dimensional photonic crystals (square and triangular lattices of Si nanopillars) with photonic band gaps in the visible and near infrared regions. We measured reflection spectra of the photonic crystals and observed polarization-dependent reflection bands in the wavelength range consistent with theoretical calculations.
Formation of Nanostructures in Silicon by Nanosecond-Pulsed Laser Irradiation
Authors: Fowlkes J. D. , Pedraza A. J. , Jesse S. , Rouleau C. M. , Blom D. A. 
Published: April 2011

AbstractSilicon nanoparticles are formed during pulsed laser ablation under a background atmosphere of Ar gas. In this paper we have characterized the nanoparticles that are backscattered via collisions in the gas phase and redeposited on the target surface. Clustering in an O2/Ar gas atmosphere resulted in the formation of unique nanostructures that photoluminesce in the violet and blue-green portions of the electromagnetic spectrum. Ablating a (001) Si target in the presence of ultra-high purity (UHP) argon produced Si nanoparticles outside the irradiated region. The mean diameter of these particles decreases from 50 nm to 5 nm with increasing distance from the laser spot. The nanoparticle distribution can be induced to self-organize in linear arrays by simultaneously irradiating the nanoparticles as they deposit.
Exciton-mediated excitation of Er3+ in Erbium-doped silicon rich silicon oxide
Authors: Seo Se-Young , Shin Jung H. 
Published: April 2011

AbstractExciton-mediated excitation of Er3+ in erbium doped silicon rich silicon oxide (SRSO) is investigated. Er-doped SRSO films were fabricated by electron cyclotron-resonance plasmaenhanced chemical vapor deposition of Er-doped SiOx (x < 2) using SiH4 and O2 as source gases and co-sputtering of Er, followed by an anneal at 950 °C. Very weak visible luminescence from Si nanocluster relative to Er3+ luminescence were observed, indicating a very efficient excitation of Er3+ ions by Si nanoclusters. From detailed modeling and analysis of time-resolved Er3+ luminescence as the excitation duration and excitation power, we conclude that exciton-erbium coupling is dominant over exciton-nanocluster. The results are consistent with the proposal that the luminescent Er3+ ions are located predominantly in the SiO2 layer.
Studies of Compositional Variations in Germanium Quantum Dots Grown on Silicon
Authors: Dunbar Alan D.F. , Halsall Matthew P. , Bangert Uschi , Harvey Alan , Dawson Philip , Joyce Bruce A. , Zhang Jing , Berbezier Isabel 
Published: April 2011

AbstractWe report optical and scanning transmission electron microscopy studies of germanium dots grown on silicon. In an attempt to control the self-organized growth process and promote dot size uniformity the dot layers were grown on a 4.5nm Si0.6Ge0.4 alloy template layer. Photoluminescence results indicate the formation of carrier confining Ge rich islands, whilst Raman scattering results indicate the presence of an alloy throughout the structures formed. The samples were studied in the UK high resolution scanning transmission electron microscopy facility at Liverpool, UK. Energy dispersive analysis of individual line scans through the sample show that the structures are composed of an alloy throughout with an asymmetric distribution of Germanium in the dots and in the wetting layer close to the dots. We discuss the results in the light of the proposed growth mode for these dots and conclude that attempts to manipulate the composition of these dots during growth may be problematic due to the self-organized nature of their formation.
Optical Photoluminescence due to the Recombination of Donor-Acceptor Pairs in Porous Silicon
Authors: Zheng J. P. , Wei X. 
Published: April 2011

AbstractThe temperature dependence of the intensity, peak-wavelength, and bandwidth of photoluminescence (PL) spectra was studied in the porous silicon (PS) sample. To explain the observed temperature dependence, we proposed a model for the origin of the PL in PS. At low temperatures, the photon emission was dominated by the recombination of donor-acceptor pairs with ionization energies of about 4 meV. The donor and the acceptor were spatially separated with a distance of about 3.8 nm, which was about the crystalline size of the PS. Whereas at high temperatures where thermal energy exceeded the ionization energy, the photon emission was mainly from the exciton recombination.
Photonic bandgap effect in Periodic Porous Silicon Planar Waveguides
Authors: Ferrand P. , Romestain R. 
Published: April 2011

AbstractWe have obtained a porous silicon optical planar waveguide, with a submicronic periodic modulation of the optical index along one direction of plane, using a holographic process. Near-infrared continuous transmission spectra of guided light across not less than 3000 periods show several strong stopbands, with a decrease of intensity by two orders of magnitude. By means of the coupled-mode theory, we were able to deduce from the spectra a realistic map of the optical index at a microscopic scale, demonstrating a strong photo-induced index contrast (Δn = 0.5) at a submicronic scale.