Hydrophobicity and transparency of Al2O3-based poly-tetra-fluoro-ethylene composite thin films using aerosol deposition

Alumina and polytetrafluoroethylene (Al₂O₃-PTFE) composite films were fabricated by a simple aerosol deposition (AD) process, to confirm its applicability for various display screens requiring water resistant, anti-smudge and easy-to-clean properties. The surface morphologies, hydrophobic properties, and transparencies of the composite films with different PTFE contents, varying from 0.01 to 1?wt% were investigated. As a result, the composite films with over 0.3?wt% PTFE showed a sudden rise in surface roughness and low transmittance, despite having the highest contact angle of 128° at a PTFE content of 0.3?wt%. From the energy dispersive spectrometer analysis, the crash-cushioning effect of PTFE and agglomerated PTFE particles were determined to be major causes of surface roughness and opacity. In contrast, the transmittance showed a tendency to be enhanced, with an increasing PTFE content in the range of 0.01, 0.05, and 0.1?wt% PTFE, respectively. Especially, the film with 0.1?wt% of PTFE had contact angle of 111° and exhibited a high transmittance of over 75%, which was inferred to be an appropriate amount of PTFE, with a high elongation filling up the surface and the internal defects, leading to an enhancement of transparency. Consequently, these results implied that the AD-prepared Al₂O₃-PTFE composite coatings are promising candidates for various display applications.     

Fabrication and characterization of nano-channel field effect transistors patterned by AFM anodic oxidation

We report a top-down approach based on atomic force microscope (AFM) local anodic oxidation (LAO) for the fabrications of the nanowire and nano-ribbon field effect transistors (FETs). In order to investigate the transport characteristics of nano-channel, we fabricated simple FET structures with channel width W approximately 300 nm (nanowire) and 10 microm (nano-ribbon) on 20 nm-thick silicon-on-insulator (SOL) wafers. In order to investigate the transport behavior in the device with different channel geometries, we have performed detailed two-dimensional simulations of nanowire and reference nano-ribbon FETs with a fixed channel length L and thickness t but varying channel width W from 300 nm to 10 microm. By evaluating the charge distributions, we have shown that the increase of 'on state' conduction current in SiNW channel is a dominant factor, which consequently result in the improved on/off current ratio of the nanowire FET.     

Metal work-function-dependent barrier height of Ni contacts with metal-embedded nanoparticles to 4H-SiC

Metal, typically gold [Au], nanoparticles [NPs] embedded in a capping metal contact layer onto silicon carbide [SiC] are considered to have practical applications in changing the barrier height of the original contacts. Here, we demonstrate the use of silver [Ag] NPs to effectively lower the barrier height of the electrical contacts to 4H-SiC. It has been shown that the barrier height of the fabricated SiC diode structures (Ni with embedded Ag-NPs) has significantly reduced by 0.11 eV and 0.18 eV with respect to the samples with Au-NPs and the reference samples, respectively. The experimental results have also been compared with both an analytic model based on Tung's theory and physics-based two-dimensional numerical simulations.     

Flavonoids from Pueraria mirifica roots and quantitative analysis using HPLC

The flavonoids, wighteone (1), naringenin (2), genistein (3), isoliquiritigenin (4), daidzein (5), daidzin (6), genistein-8-C-β-d-apiofuranosyl-(1→6)-O-β-d-glucopyranoside (7), ambocin (8), and genistin (9) were isolated from roots of Pueraria mirifica. Chemical structures of the compounds were determined based on spectroscopic data analysis. Flavonoids 1, 2, 4, 7, and 8 were isolated for the first time. The contents of 6 flavonoids in P. mirifica roots was determined to be 2.5±0.01 (1), 14.8±0.09 (3), 18.6±0.18 (5), 17.3±0.11 (6), 10.4±0.05 (7), and 6.0±0.02 (9) mg/kg, respectively, using HPLC.     

Enhancing citation recommendation using citation network embedding

Scientometrics - Automatic recommendation of citations has been a focal point of research in scholarly digital libraries. Many graph-based citation recommendation algorithms have been proposed;...     

Nano-structure fabrication of GaAs using AFM tip-induced local oxidation method: different doping types and plane orientations

In this study, we have fabricated nano-scaled oxide structures on GaAs substrates that are doped in different conductivity types of p- and n-types and plane orientations of GaAs(100) and GaAs(711), respectively, using an atomic force microscopy (AFM) tip-induced local oxidation method. The AFM-induced GaAs oxide patterns were obtained by varying applied bias from approximately 5 V to approximately 15 V and the tip loading forces from 60 to 180 nN. During the local oxidation, the humidity and the tip scan speed are fixed to approximately 45% and approximately 6.3 μm/s, respectively. The local oxidation rate is further improved in p-type GaAs compared to n-type GaAs substrates whereas the rate is enhanced in GaAs(100) compared to and GaAs(711), respectively, under the identical conditions. In addition, the oxide formation mechanisms in different doping types and plane orientations were investigated and compared with two-dimensional simulation results.