From the previous studies, one of the challenges in the oxide vapor phase epitaxy (OVPE) method was suppressing poly-crystal generation for thick GaN growth. In this study, thick GaN growth was realized by controlling the supersaturation ratio using thermodynamic analysis, and an OVPE-GaN wafer of 300 μm-thick was obtained. As a result of evaluating the quality of the OVPE-GaN wafer, it was confirmed that both the high oxygen concentration and the high crystallinity were achieved. The resistivity was 7.75 × 10 −4 Ω cm and the threading dislocation density (TDD) was 8.8 × 10 4 cm −2 . It was newly found that the OVPE method can reduce TDD from the order of 10 6 cm −2 to the order of 10 4 cm −2 with a grown thickness of less than 500 μm. From these results, it was proved that the OVPE method has a great potential of manufacturing low resistivity and low TDD GaN wafers.

III-N semiconductors growth on high quality ScAlMgO 4 (SCAMO) substrates was studied. The GaN epitaxial layer grown on the SCAMO substrate showed a low defect density of 5.6 × 10 7 cm −2 evaluated by cathode luminescence and had a distinct improvement in crystallinity compared to the GaN layer on a sapphire substrate. LEDs on both SCAMO and sapphire substrates were grown, and their optical properties were compared. The LED on the SCAMO substrate showed high luminescence efficiency by photoluminescence, and it was 14.3% at 300 K. Bright emission from the LED on the SCAMO substrate was observed under current injection and the electroluminescence properties revealed that the external efficiency of the LED on the SCAMO substrate was 15% higher than that of the LED on the sapphire substrate.

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Fort he creation of next-generation organic electronic materials,t he integration of p-systems has recently become ac entral theme.S uch functional materials can be assembled by supramolecular polymerization when aromatic p-systems are used as monomers,a nd the properties of the resulting supramolecular polymer strongly depend on the electronic structure of the monomers.Here,wedemonstrate the construction of as upramolecular polymer consisting of an antiaromatic p-system as the monomer.A na mide-functionalized Ni II norcorrole derivative formed ao ne-dimensional supramolecular polymer through p-p stacking and hydrogenbonding interactions,e nsuring the persistency of the conducting pathway against thermal perturbation, which results in higher charge mobility along the tightly bound linear aggregates than that of the aromatic analogue composed of Zn II porphyrins.

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Porous frameworks composed of non‐stoichiometrically mixed multicomponent molecules attract much attention from a functional viewpoint. However, their designed preparation and precise structural characterization remain challenging. Herein, we demonstrate that cocrystallization of tetrakis(4‐carboxyphenyl)hexahydropyrene and pyrene derivatives (CP‐Hp and CP‐Py, respectively) yields non‐stoichiometric mixed frameworks through networking via hydrogen bonding. The composition ratio of CP‐Hp and CP‐Py in the framework was determined by single crystalline X‐ray crystallographic analysis, indicating that the mixed frameworks were formed over a wide range of composition ratios. Furthermore, microscopic Raman spectroscopy on the single crystal indicates that the components are not uniformly distributed such as ideal solid solution, but are done gradationally or inhomogeneously.

The critical dimension of semiconductor devices is approaching the single-nm regime, and a variety of practical devices of this scale are targeted for production. Planar structures of nano-devices are still the center of fabrication techniques, which limit further integration of devices into a chip. Extension into 3D space is a promising strategy for future; however, the surface interaction in 3D nanospace make it hard to integrate nanostructures with ultrahigh aspect ratios. Here we report a unique technique using high-energy charged particles to produce free-standing 1D organic nanostructures with high aspect ratios over 100 and controlled number density. Along the straight trajectory of particles penetrating the films of various sublimable organic molecules, 1D nanowires were formed with approximately 10~15 nm thickness and controlled length. An all-dry process was developed to isolate the nanowires, and planar or coaxial heterojunction structures were built into the nanowires. Electrical and structural functions of the developed standing nanowire arrays were investigated, demonstrating the potential of the present ultrathin organic nanowire systems.

Preparation and characterizationfp orous frameworks composed of non-stoichiometrically mixed multicomponent molecules has been ac hallenge.I nt heir Communication (e202215836), Ichiro Hisaki et al. demonstrate that cocrystallization of hexahydropyrene and pyrene derivatives yields such frameworks through ahydrogen-bonded network. Thecomposition ratio in the framework was determined crystallographically.