Addressing diffusion behavior and impact in an epoxy-amine cure system using molecular dynamics simulations.

To deepen understanding of diffusion-controlled crosslinking, molecular dynamics (MD) simulations are carried out by taking the diffusion image of 3,3'-diamino diphenyl sulfone (3,3'-DDS) and polyethersulfone (PES) with epoxy resin varying temperatures from 393.15 to 473.15 K over crosslinking conversion of 0-85%.

High-Throughput Growth of Wafer-Scale Monolayer Transition Metal Dichalcogenide via Vertical Ostwald Ripening.

For practical device applications, monolayer transition metal dichalcogenide (TMD) films must meet key industry needs for batch processing, including the high-throughput, large-scale production of high-quality, spatially uniform materials, and reliable integration into devices. Here, high-throughput growth, completed in 12 min, of 6-inch wafer-scale monolayer MoS and WS is reported, which is directly compatible with scalable batch processing and device integration. Specifically, a pulsed metal-organic chemical vapor deposition process is developed, where periodic interruption of the precursor supply drives vertical Ostwald ripening, which prevents secondary nucleation despite high precursor concentrations.

Ultralow-dielectric-constant amorphous boron nitride.

Decrease in processing speed due to increased resistance and capacitance delay is a major obstacle for the down-scaling of electronics. Minimizing the dimensions of interconnects (metal wires that connect different electronic components on a chip) is crucial for the miniaturization of devices. Interconnects are isolated from each other by non-conducting (dielectric) layers.

Characteristics of ZrC Barrier Coating on SiC-Coated Carbon/Carbon Composite Developed by Thermal Spray Process.

A thick ZrC layer was successfully coated on top of a SiC buffer layer on carbon/carbon (C/C) composites by vacuum plasma spray (VPS) technology to improve the ablation resistance of the C/C composites. An optimal ZrC coating condition was determined by controlling the discharge current. The ZrC layers were more than 70 µm thick and were rapidly coated under all spraying conditions.

High-performance and scalable metal-chalcogenide semiconductors and devices via chalco-gel routes.

We report a general strategy for obtaining high-quality, large-area metal-chalcogenide semiconductor films from precursors combining chelated metal salts with chalcoureas or chalcoamides. Using conventional organic solvents, such precursors enable the expeditious formation of chalco-gels, which are easily transformed into the corresponding high-performance metal-chalcogenide thin films with large, uniform areas. Diverse metal chalcogenides and their alloys (MQ : M = Zn, Cd, In, Sb, Pb; Q = S, Se, Te) are successfully synthesized at relatively low processing temperatures (<400°C).

Degradation by water vapor of hydrogenated amorphous silicon oxynitride films grown at low temperature.

We report on the degradation process by water vapor of hydrogenated amorphous silicon oxynitride (SiON:H) films deposited by plasma-enhanced chemical vapor deposition at low temperature. The stability of the films was investigated as a function of the oxygen content and deposition temperature. Degradation by defects such as pinholes was not observed with transmission electron microscopy.

Direct evidence of flat band voltage shift for TiN/LaO or ZrO/SiO stack structure via work function depth profiling.

We demonstrated that a flat band voltage (V) shift could be controlled in TiN/(LaO or ZrO)/SiO stack structures. The V shift described in term of metal diffusion into the TiN film and silicate formation in the inserted (LaO or ZrO)/SiO interface layer. The metal doping and silicate formation confirmed by using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) line profiling, respectively.

Chemically Homogeneous and Thermally Robust NiPtSi Film Formed Under a Non-Equilibrium Melting/Quenching Condition.

To synthesize a thermally robust NiPtSi film suitable for ultrashallow junctions in advanced metal-oxide-semiconductor field-effect transistors, we used a continuous laser beam to carry out millisecond annealing (MSA) on a preformed Ni-rich silicide film at a local surface temperature above 1000 °C while heating the substrate to initiate a phase transition. The melting and quenching process by this unique high-temperature MSA process formed a NiPtSi film with homogeneous Pt distribution across the entire film thickness. After additional substantial thermal treatment up to 800 °C, the noble NiPtSi film maintained a low-resistive phase without agglomeration and even exhibited interface flattening with the underlying Si substrate.

Defect visualization of Cu(InGa)(SeS)2 thin films using DLTS measurement.

Defect depth profiles of Cu (In1-x,Gax)(Se1-ySy)2 (CIGSS) were measured as functions of pulse width and voltage via deep-level transient spectroscopy (DLTS). Four defects were observed, i.e.

Self-arrangement of nanoparticles toward crystalline metal oxides with high surface areas and tunable 3D mesopores.

We demonstrate a new design concept where the interaction between silica nanoparticles (about 1.5 nm in diameter) with titania nanoparticles (anatase, about 4 nm or 6 nm in diameter) guides a successful formation of mesoporous titania with crystalline walls and controllable porosity. At an appropriate solution pH (~1.

Advanced hybrid supercapacitor based on a mesoporous niobium pentoxide/carbon as high-performance anode.

Recently, hybrid supercapacitors (HSCs), which combine the use of battery and supercapacitor, have been extensively studied in order to satisfy increasing demands for large energy density and high power capability in energy-storage devices. For this purpose, the requirement for anode materials that provide enhanced charge storage sites (high capacity) and accommodate fast charge transport (high rate capability) has increased. Herein, therefore, a preparation of nanocomposite as anode material is presented and an advanced HSC using it is thoroughly analyzed.

Simple fabrication of flexible electrodes with high metal-oxide content: electrospun reduced tungsten oxide/carbon nanofibers for lithium ion battery applications.

A one-step and mass-production synthetic route for a flexible reduced tungsten oxide-carbon composite nanofiber (WO(x)-C-NF) film is demonstrated via an electrospinning technique. The WO(x)-C-NF film exhibits unprecedented high content of metal-oxides (∼ 80 wt%) and good flexibility (the tensile strength of the specimen was 6.13 MPa) without the use of flexible support materials like CNTs or graphene.

Lead-free BaTiO3 nanowires-based flexible nanocomposite generator.

We have synthesized BaTiO3 nanowires (NWs) via a simple hydrothermal method at low temperature and developed a lead-free, flexible nanocomposite generator (NCG) device by a simple, low-cost, and scalable spin-coating method. The hydrothermally grown BaTiO3 NWs are mixed in a polymer matrix without a toxic dispersion enhancer to produce a piezoelectric nanocomposite (p-NC). During periodical and regular bending and unbending motions, the NCG device fabricated by utilizing a BaTiO3 NWs-polydimethylsiloxane (PDMS) composite successfully harvests the output voltage of ∼ 7.

Nanocrystalline ZnON; high mobility and low band gap semiconductor material for high performance switch transistor and image sensor application.

Interest in oxide semiconductors stems from benefits, primarily their ease of process, relatively high mobility (0.3-10 cm(2)/vs), and wide-bandgap. However, for practical future electronic devices, the channel mobility should be further increased over 50 cm(2)/vs and wide-bandgap is not suitable for photo/image sensor applications.

Effects of interfacial layer on characteristics of TiN/ZrO2 structures.

To minimize the formation of unwanted interfacial layers, thin interfacial layer (ZrCN layer) was deposited between TiN bottom electrode and ZrO2 dielectric in TiN/ZrO2/TiN capacitor. Carbon and nitrogen were also involved in the layer because ZrCN layer was thermally deposited using TEMAZ without any reactant. Electrical characteristics of TiN/ZrO2/TiN capacitor were improved by insertion of ZrCN layer.

Catalytic conversion of 1,2-dichlorobenzene over mesoporous materials from zeolite.

In this study, 1,2-dichlorobenzene (DCB), an important precursor of PCDDs and PCDFs, was chosen as a suitable model compound for the catalyzed deep oxidation of dioxin. The recently developed mesoporous materials from zeolites (MMZ) were used for the first time as a support for an oxidation catalyst. The catalytic oxidation of 1,2-dichlorobenzene over Pt/MMZ was carried out, and the catalytic activity was compared with that of Pt/gamma-Al2O3, Pt/Al-MCM-41 and Pt/Beta catalysts.

Low-temperature pseudomorphic transformation of ordered hierarchical macro-mesoporous SiO2/C nanocomposite to SiC via magnesiothermic reduction.

A magnesiothermic reduction synthesis approach is reported for direct conversion of SiO(2)/C composite nanostructures to corresponding SiC materials without losing their nanostructure morphologies. Crystalline SiC materials can be obtained by this approach at a temperature as low as 600 degrees C, only approximately half of that applied in the generally used carbothermal reduction and preceramic polymer pyrolysis methods. An ordered hierarchical macro-mesoporous SiC material was synthesized for the first time as a demonstration.

Application of ordered nanoporous silica for removal of uranium ions from aqueous solutions.

Ordered nanoporous silica (MSU-H) with high surface area has been utilized as a solid substrate of a surface-modified hybrid sorbent for the application to the removal of U(VI). Carboxymethylated polyethyleneimine (CMPEI) with a strong complexing property has been introduced to the pore surface of MSU-H substrate. CMPEI-modified MSU-H (CMPEI/MSU-H) has been characterized by scanning electron microscopy and nitrogen sorption.

Periodic mesoporous organosilica with a hexagonally pillared lamellar structure.

Ordered mesoporous materials (OMMs) with well-defined pore sizes (>2 nm) and pore geometries are important in various applications that require fast mass transfer or deal with large molecules. Extensive research has resulted in the discovery of OMMs with three types of mesostructures: (i) bi- or multicontinuous, (ii) columnar, and (iii) discontinuous (cagelike). However, another type, the pillared lamellar structure, which has long been sought and has been mathematically computed and known to exist in the research fields of surfactant and multiblock-copolymer mesophases, still remains a mesostructure that has not been observed in real OMMs for any specific symmetry.

Synthesis of nanoporous material from zeolite USY and catalytic application to bio-oil conversion.

A highly ordered nanoporous aluminosilicate (MMZ(USY)) was synthesized using commercially available zeolite USY as the framework source and cetyltrimethylammonium bromide as the template. The aluminosilicate was characterized by XRD, N2 adsorption, ICP-AES and TPD. The catalytic performance of the MMZ(USY) material in the conversion of bio-oil was compared with that of Al-MCM-41, which was synthesized using a direct sol-gel method.

Rational design of ordered mesoporous carbon with controlled bimodal porosity via dual silica templating route.

Combining both nano-replication and nano-imprinting techniques using dual silica templates provides a simple way to synthesize ordered mesoporous carbons with bimodal pore size distributions ( approximately 1.5 nm and approximately 3.5 nm).

Direct synthesis of ordered mesoporous materials constructed with polymer-silica hybrid frameworks.

Highly ordered mesoporous materials constructed with integrated polymer-silica hybrid frameworks can be obtained via a one-step synthetic strategy using a mixture of polymer and silicate as the framework sources in the presence of a structure-directing agent.

Reversible replication between ordered mesoporous silica and mesoporous carbon.

Highly ordered mesoporous silica can be regenerated from a mesoporous carbon CMK-3 that is a negative replica of mesoporous silica SBA-15, indicating reversible replication between carbon and inorganic materials.