Search

A capacitive-type touch screen panel (TSP) composed of silver nanowire (AgNW) crossing electrodes and transparent bridge structures was fabricated on a polycarbonate film. The transparent bridge structure was formed with a stack of Al-doped ZnO (AZO) electrodes and SU-8 insulator. The stable and robust continuity of the bridge electrode over the bridge insulator was achieved by making the side-wall slope of the bridge insulator low and depositing the conformal AZO film with atomic layer deposition. With an extended exposure time of photolithography, the lower part of the SU-8 layer around the region uncovered by the photomask can be exposed enough to the UV light scattered from the substrate. This leads to the low side-wall slope of the bridge insulator. The fabricated TSP sample showed a large capacitance change of 22.71% between with and without touching. Our work supplies the technological clue for ensuring long-term reliability to the highly flexible and transparent TSP made by using conventional fabrication processes.

Four solvent-responsive one-dimensional copper(I) coordination polymers (CPs), namely, {[Cu4I4L(MeCN)2]·CH2Cl2}n (1), {[Cu4I4L(MeCN)2]·CHCl3}n (2), {[Cu4I4L(MeCN)2]·0.5p-xylene}n (3), and [Cu4I4L(MeCN)2]n (4), were prepared by reaction of CuI with N,N′-bis[2-(cyclohexylthio)ethyl]pyromellitic diimide (L) via self-assembly under varying solvent conditions. CPs 1–4, which are pseudopolymorphic supramolecular isomers derived from solvent molecules, are composed of Cu4I4 cubane clusters. The ligands in CPs 1–3 adopted a syn-conformation, whereas in CP 4 they were observed in the anti-conformation. This occurred via syn to anti transitions upon heating, followed by exposure to MeCN vapor. In addition, a reversible anti to syn transition was achieved by agitating in mixed organic solvents. It was shown that ligand transition from the syn- to the anti-conformation occurred through crystal-to-amorphous-to-crystal transformations. Furthermore, CPs 1–3 exhibited reversible solvent exchange and crystal transformatio...

Terahertz (THz) detectors have been extensively studied for various applications such as security, wireless communication, and medical imaging. In case of metal-insulator-metal (MIM) tunnel junction THz detector, a small junction area is desirable because the detector response time can be shortened by reducing it. An edge metal-semiconductor-metal (EMSM) junction has been developed with a small junction area controlled precisely by the thicknesses of metal and semiconductor films. The voltage response of the EMSM THz detector shows the clear dependence on the polarization angle of incident THz wave and the responsivity is found to be very high (~2,169 V/W) at 0.4 THz without any antenna and signal amplifier. The EMSM junction structure can be a new and efficient way of fabricating the nonlinear device THz detector with high cut-off frequency relying on extremely small junction area.

The controlled self-assembly of CuI and an asymmetric ligand with mixed N/S donors, 2-(tert-butylthio)-N-(pyridin-3-yl)acetamide (L), afforded three Cu(I) coordination polymers (CPs), [Cu4I4L2(MeCN)2]n (1), [Cu4I4L2]n (2), and {[Cu4I4L2]⋅MeOH}n (3). X-ray analyses showed that CPs 1-3 are supramolecular isomers with 1, 2, and 3D structures, respectively. CP 1 adopts a stairstep Cu4I4 cluster, whereas CPs 2 and 3 are composed of cubane-like Cu4I4 clusters. Crystal-to-crystal transformations of 1 to 2 and 3 showed reversible transformations between different Cu4I4 clusters using heat or solvent (acetonitrile or methanol) vapor. CP 2 was reversibly transformed to 3 by the addition of methanol and heat. Therefore, the transformations between supramolecular isomers 1, 2, and 3 are completely reversible.

Four copper(I) coordination polymers (CPs), {[CuIL]·CH3CN]}n (1), {[CuIL]·CHCl3}n (2), {[CuIL]·CH2Cl2}n (3), and [CuIL]n (4), were prepared by self-assembly reactions between CuI and (2-pyrazinylcarbonyl)thiomorpholine (L). CPs 1–4 are interconnected by rhomboid Cu–I2–Cu units. CPs 1 and 4 have one-dimensional loop-chain structures, and 2 and 3 adopt two-dimensional network structures. CPs 1–4 are pseudopolymorphic supramolecular isomers. CPs 2′ and 3′ are prepared by removal of solvate molecules from CPs 2 and 3, which are polymorphic supramolecular isomers with CP 4. Reversible crystal-to-crystal transformations were observed under appropriate conditions such as solvent or heat.

A two-dimensional network stair-step Cu4I4 coordination polymer (1) based on 1,4-bis((methylthio)propanoyl)piperazine was prepared. No emission was observed from 1 (off state), while a heated sample (2) of 1 emitted a strong green light (on state). Conversion between 1 and 2 was reversible upon removal of acetonitrile or exposure of 2 to acetonitrile.

From the reaction of CuI with an N,S-donor ligand (L) under different molar ratios, two discrete polynuclear copper(I) iodide complexes, [Cu2I2L2] (1) and [Cu7I7L3] (2) were isolated and characterised. Complex 1 contains a rhomboid-type Cu2I2 cluster, whilst complex 2 is the first example showing a pinwheel-type Cu7I7 cluster.

We report the systematic experimental studies demonstrating that a graphene layer inserted at metal/n-Si(001) interface is efficient to explore interface Fermi-level pinning effect. It is confirmed that an inserted graphene layer prevents atomic interdiffusion to form an atomically abrupt Schottky contact. The Schottky barriers of metal/graphene/n-Si(001) junctions show a very weak dependence on metal work-function, implying that the metal Fermi-level is almost completely pinned at charge neutrality level close to the valence band edge of Si. The atomically impermeable and electronically transparent properties of graphene can be used generally to form an intact Schottky contact for all semiconductors.

An enormous amount of research activities has been devoted to developing new types of non-volatile memory devices as the potential replacements of current flash memory devices. Theoretical device modeling was performed to demonstrate that a huge change of tunnel resistance in an Edge Metal-Insulator-Metal (EMIM) junction of metal crossbar structure can be induced by the modulation of electric fringe field, associated with the polarization reversal of an underlying ferroelectric layer. It is demonstrated that single three-terminal EMIM/Ferroelectric structure could form an active memory cell without any additional selection devices. This new structure can open up a way of fabricating all-thin-film-based, high-density, high-speed, and low-power non-volatile memory devices that are stackable to realize 3D memory architecture.

The title compound {systematic name: 1-(4,6-dimethoxypyrimidin-2-yl)-3-[1-methyl-4-(2-methyl-2H-tetrazol-5-yl)pyrazol-5-ylsulfonyl]urea}, C13H16N10O5S, is a sulfonylurea herbicide. In this compound, the dihedral angles between the planes of the central pyrazole and the terminal dimethoxypyrimidine and tetrazole rings are 79.10 (8) and 17.21 (16)°, respectively. In the crystal, N—H...O hydrogen bonds link adjacent molecules, formingR22(8) inversion dimers. In addition, weak C—H...O and C—H...N hydrogen bonds and weak π–π interactions [ring centroid separation = 3.8255 (12) Å] are present, resulting in a three-dimensional architecture.

The crystallinity of epitaxial graphene (EG) grown on a Hexagonal-SiC substrate is found to be enhanced greatly by capping the substrate with a molybdenum plate (Mo-plate) during vacuum annealing. The crystallinity enhancement of EG layer grown with Mo-plate capping is confirmed by the significant change of measured Raman spectra, compared to the spectra for no capping. Mo-plate capping is considered to induce heat accumulation on SiC surface by thermal radiation mirroring and raise Si partial pressure near surface by confining the sublimated Si atoms between SiC substrate and Mo-plate, which would be the essential contributors of crystallinity enhancement.

In the title compound {systematic name: 2-[(3,5,6-trichloropyridin-2-yl)oxy]acetic acid}, the herbicide triclopyr, C7H4Cl3NO3, the asymmetric unit comprises two independent molecules in which the dihedral angles between the mean plane of the carboxylic acid group and the pyridyl ring plane are 79.3 (6) and 83.8 (5)°. In the crystal, pairs of intermolecular O—H...O hydrogen bonds form dimers through anR22(8) ring motif and are extended into chains along [100] by weak π–π interactions [ring centroid separations = 3.799 (4) and 3.810 (4) Å]. In addition, short intermolecular Cl...Cl contacts [3.458 (2) Å] connect the chains, yielding a two-dimensional architecture extending parallel to (020). The crystal studied was found to be non-merohedrally twinned with the minor component being 0.175 (4).

The title compound, C22H22ClN3O5{systematic name: 2-(propan-2-ylideneaminooxy)ethyl (R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propionate}, is a herbicide. The asymmetric unit comprises two independent molecules in which the dihedral angles between the phenyl ring and the quinoxaline ring plane are 75.93 (7) and 82.77 (8)°. The crystal structure features C—H...O, C—H...N, and C—H...Cl hydrogen bonds, as well as weak π–π interactions [ring-centroid separation = 3.782 (2) and 3.5952 (19) Å], resulting in a three-dimensional architecture.

The Au/Ni/Al2O3/4H-SiC junction with the Al2O3 film as a thin spacer layer was found to show the electrical characteristics of a typical rectifying Schottky contact, which is considered to be due to the leakiness of the spacer layer. The Schottky barrier of the junction was measured to be higher than an Au/Ni/4H-SiC junction with no spacer layer. It is believed that the negative surface bound charge originating from the spontaneous polarization of 4H-SiC causes the Schottky barrier increase. The use of a thin spacer layer can be an efficient experimental method to modulate Schottky barriers of metal/4H-SiC junctions.

The complete molecule of the title compound, C14H8N2, is generated by a twofold rotation axis located at the midpoint of the biphenyl C—C bond. The dihedral angle between the symmetry-related phenyl rings is 46.16 (3)°. In the crystal, molecules are linked by slipped parallel π–π interactions [centroid–centroid distance = 3.9451 (7) Å, normal distance = 3.6293 (5) Å, slippage 1.547 Å], forming columns along theb-axis direction.

In the title compound, C14H15N3(systematic name: 4-cyclopropyl-6-methyl-N-phenylpyrimidin-2-amine), which is the anilinopyrimidine fungicide cyprodinil, the dihedral angles between the planes of the central pyrimidine ring and the terminal phenyl ring and the mean plane of the cyclopropane ring system are 14.52 (11) and 88.79 (10)°, respectively. In the crystal, weak π–π interactions [3.8551 (11) Å] connect the dimers into chains along theb-axis direction.

In the title compound, the herbicide bifenox, C14H9Cl2NO5, the dihedral angle between the dichlorobenzene and nitrobenzene rings is 78.79 (14)°. In the crystal, C—H...O hydrogen bonds give rise to a three-dimensional network structure in which there are both a π–π interaction [ring centroid separation = 3.6212 (16) Å] and a C—Cl...π interaction [Cl...ring centroid = 3.4754 (8) Å]. In addition, short Cl...Cl contacts [3.3767 (11) and 3.3946 (11) Å] are present.

In the asymmetric unit of the title compound {systematic name: N′-(2,4-dimethylphenyl)-N-[N-(2,4-dimethylphenyl)carboximidoyl]-N-methylmethanimidamide}, C19H23N3, which is a formamidine pesticide, there are two independent and conformationally similar molecules, with the dihedral angle between the mean planes of the 2,4-dimethylbenzene rings in each molecule being 41.63 (6) and 42.09 (5)°. The crystal structure is stabilized by a C—H...N hydrogen bond, as well as weak intermolecular C—H...π and π–π interactions [ring centroid separation = 3.7409 (15) Å], giving one-dimensional chains extending down the b direction.

In the title compound, C(22)H(26)O(3), the dihedral angle between the cyclo-propane ring and the plane of the vinyl group is 88.2 (2)°. The dihedral angle between the phenyl and furan rings is 86.09 (8)°. In the crystal, weak inter-molecular C-H⋯π contacts together with very weak C-H⋯O hydrogen bonds stack the mol-ecules along the a axis.

It is observed that epitaxial graphene forms on the surface of a 6H-SiC substrate by irradiating electron beam directly on the sample surface in high vacuum at relatively low temperature (∼670 °C). The symmetric shape and full width at half maximum of 2D peak in the Raman spectra indicate that the formed epitaxial graphene is turbostratic. The gradual change of the Raman spectra with electron beam irradiation time increasing suggests that randomly distributed small grains of epitaxial graphene form first and grow laterally to cover the entire irradiated area. The sheet resistance of epitaxial graphene film is measured to be ∼6.7 kΩ/sq.

Ballistic electron emission microscopy was used to measure the increase of local Schottky barrier (compared to the surrounding 4H-SiC area) over a partial 8H-SiC layer that is the surface-exposed tail of an 8H stacking fault inclusion extending from 4H substrate. This local increase is believed to be due to polarization charge induced at the interface of partial 8H layer and underlying 4H host, resulting from the spontaneous polarization (SP) difference between SiC regions with different bilayer stacking. This is a direct experimental probe of the dependence of SP in SiC on local stacking sequence by measuring carrier transport.