Ultraclean Interface of Metal Chalcogenides with Metal through Confined Interfacial Chalcogenization.

Acquisition of defect-free transition metal dichalcogenides (TMDs) channels with clean heterojunctions is a critical issue in the production of TMD-based functional electronic devices. Conventional approaches have transferred TMD onto a target substrate, and then apply the typical device fabrication processes. Unfortunately, those processes cause physical and chemical defects in the TMD channels.

Saliency as Pseudo-Pixel Supervision for Weakly and Semi-Supervised Semantic Segmentation.

Existing studies on semantic segmentation using image-level weak supervision have several limitations, including sparse object coverage, inaccurate object boundaries, and co-occurring pixels from non-target objects. To overcome these challenges, we propose a novel framework, an improved version of Explicit Pseudo-pixel Supervision (EPS++), which learns from pixel-level feedback by combining two types of weak supervision. Specifically, the image-level label provides the object identity via the localization map, and the saliency map from an off-the-shelf saliency detection model offers rich object boundaries.

Development of a preliminary environmental risk assessment system by using text mining for introducing alien crops.

Changes in worldwide crop trends and climate change has increased the introduction of alien crops. However, there are always potential side effect issues related to introduced crops, such as the introduced crop becoming a nuisance at the new country or bringing insect pests or microorganisms with the introduced crops. In this study, we developed a crop introduction risk assessment system using text mining method to prevent this problem.

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.

An Atomically Thin Optoelectronic Machine Vision Processor.

2D semiconductors, especially transition metal dichalcogenide (TMD) monolayers, are extensively studied for electronic and optoelectronic applications. Beyond intensive studies on single transistors and photodetectors, the recent advent of large-area synthesis of these atomically thin layers has paved the way for 2D integrated circuits, such as digital logic circuits and image sensors, achieving an integration level of ≈100 devices thus far. Here, a decisive advance in 2D integrated circuits is reported, where the device integration scale is increased by tenfold and the functional complexity of 2D electronics is propelled to an unprecedented level.

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.

Multi-criteria decision support system of the photovoltaic and solar thermal energy systems using the multi-objective optimization algorithm.

When the photovoltaic (PV) and solar thermal energy (STE) systems, which share the rooftop area, are installed in the same building, a trade-off problem occurs in terms of the energy, economic, and environmental aspects, and thus, steps need to solve this problem. Therefore, this study aimed to develop a multi-criteria decision support system of the PV and STE systems using the multi-objective optimization algorithm. This system was developed in the following six steps: (i) database establishment; (ii) designing the variables of the PV and STE systems; (iii) development of the analysis engine of the PV and STE systems; (iv) environmental and economic assessment from the life cycle perspective; (v) integrated multi-objective optimization (iMOO) with a genetic algorithm; and (vi) establishment of a multi-criteria decision support system.

Vertical MoS Double-Layer Memristor with Electrochemical Metallization as an Atomic-Scale Synapse with Switching Thresholds Approaching 100 mV.

Atomically thin two-dimensional (2D) materials-such as transition metal dichalcogenide (TMD) monolayers and hexagonal boron nitride (hBN)-and their van der Waals layered preparations have been actively researched to build electronic devices such as field-effect transistors, junction diodes, tunneling devices, and, more recently, memristors. Two-dimensional material memristors built in lateral form, with horizontal placement of electrodes and the 2D material layers, have provided an intriguing window into the motions of ions along the atomically thin layers. On the other hand, 2D material memristors built in vertical form with top and bottom electrodes sandwiching 2D material layers may provide opportunities to explore the extreme of the memristive performance with the atomic-scale interelectrode distance.

The effects of filters for an intelligent air pollutant control system considering natural ventilation and the occupants.

Experimental analysis was conducted on the indoor air pollutant concentration using natural ventilation and filters. The study targeted two office rooms each of which was occupied by four people, and with the same outdoor environments. A non-woven fabric filter (room A) and an electrostatic filter (room B) were installed on the window frame, and the indoor air pollutant concentration and indoor climate factors were monitored based on the number of occupants and the occupants' activities.

Two-Dimensional Materials Inserted at the Metal/Semiconductor Interface: Attractive Candidates for Semiconductor Device Contacts.

Metal-semiconductor junctions are indispensable in semiconductor devices, but they have recently become a major limiting factor precluding device performance improvement. Here, we report the modification of a metal/n-type Si Schottky contact barrier by the introduction of two-dimensional (2D) materials of either graphene or hexagonal boron nitride (h-BN) at the interface. We realized the lowest specific contact resistivities (ρ) of 3.

Mesostructured HfxAlyO2 Thin Films as Reliable and Robust Gate Dielectrics with Tunable Dielectric Constants for High-Performance Graphene-Based Transistors.

We introduce a reliable and robust gate dielectric material with tunable dielectric constants based on a mesostructured HfxAlyO2 film. The ultrathin mesostructured HfxAlyO2 film is deposited on graphene via a physisorbed-precursor-assisted atomic layer deposition process and consists of an intermediate state with small crystallized parts in an amorphous matrix. Crystal phase engineering using Al dopant is employed to achieve HfO2 phase transitions, which produce the crystallized part of the mesostructured HfxAlyO2 film.

Change of QT variability index during general anesthesia.

Background: The QT variability index (QTVI)-a non-invasive measure of beat-to-beat QT interval (QTI) fluctuations-is related to myocardial repolarization lability. The QTVI represents the relationship between QTI and the RR interval. Elevated QTVI is associated with an increased risk of malignant ventricular arrhythmias and sudden death.

Thickness scaling of atomic-layer-deposited HfO2 films and their application to wafer-scale graphene tunnelling transistors.

The downscaling of the capacitance equivalent oxide thickness (CET) of a gate dielectric film with a high dielectric constant, such as atomic layer deposited (ALD) HfO2, is a fundamental challenge in achieving high-performance graphene-based transistors with a low gate leakage current. Here, we assess the application of various surface modification methods on monolayer graphene sheets grown by chemical vapour deposition to obtain a uniform and pinhole-free ALD HfO2 film with a substantially small CET at a wafer scale. The effects of various surface modifications, such as N-methyl-2-pyrrolidone treatment and introduction of sputtered ZnO and e-beam-evaporated Hf seed layers on monolayer graphene, and the subsequent HfO2 film formation under identical ALD process parameters were systematically evaluated.

A Mask-Free Passivation Process for Low Noise Nanopore Devices.

Solid-state nanopores have been studied widely for the label-free analysis of single biomolecules. The translocation of charged biomolecules through a solid-state nanopore is driven by the applied voltage across a thin membrane. The ionic current changes in response to the translocation of DNA through the nanopore.

Involvement of Protein Kinase C-δ in Vascular Permeability in Acute Lung Injury.

Pulmonary edema is a major cause of mortality due to acute lung injury (ALI). The involvement of protein kinase C-δ (PKC-δ) in ALI has been a controversial topic. Here we investigated PKC-δ function in ALI using PKC-δ knockout (KO) mice and PKC inhibitors.

A low-noise solid-state nanopore platform based on a highly insulating substrate.

A solid-state nanopore platform with a low noise level and sufficient sensitivity to discriminate single-strand DNA (ssDNA) homopolymers of poly-A40 and poly-T40 using ionic current blockade sensing is proposed and demonstrated. The key features of this platform are (a) highly insulating dielectric substrates that are used to mitigate the effect of parasitic capacitance elements, which decrease the ionic current RMS noise level to sub-10 pA and (b) ultra-thin silicon nitride membranes with a physical thickness of 5 nm (an effective thickness of 2.4 nm estimated from the ionic current) are used to maximize the signal-to-noise ratio and the spatial depth resolution.

Framework for the mapping of the monthly average daily solar radiation using an advanced case-based reasoning and a geostatistical technique.

For the effective photovoltaic (PV) system, it is necessary to accurately determine the monthly average daily solar radiation (MADSR) and to develop an accurate MADSR map, which can simplify the decision-making process for selecting the suitable location of the PV system installation. Therefore, this study aimed to develop a framework for the mapping of the MADSR using an advanced case-based reasoning (CBR) and a geostatistical technique. The proposed framework consists of the following procedures: (i) the geographic scope for the mapping of the MADSR is set, and the measured MADSR and meteorological data in the geographic scope are collected; (ii) using the collected data, the advanced CBR model is developed; (iii) using the advanced CBR model, the MADSR at unmeasured locations is estimated; and (iv) by applying the measured and estimated MADSR data to the geographic information system, the MADSR map is developed.

Estimation of the monthly average daily solar radiation using geographic information system and advanced case-based reasoning.

The photovoltaic (PV) system is considered an unlimited source of clean energy, whose amount of electricity generation changes according to the monthly average daily solar radiation (MADSR). It is revealed that the MADSR distribution in South Korea has very diverse patterns due to the country's climatic and geographical characteristics. This study aimed to develop a MADSR estimation model for the location without the measured MADSR data, using an advanced case based reasoning (CBR) model, which is a hybrid methodology combining CBR with artificial neural network, multiregression analysis, and genetic algorithm.

Single-step formation of a graphene-metal hybrid transparent and electrically conductive film.

We report here a rapid (10 s of heating) graphene growth method that can be carried out on any desired substrate, including an insulator, thus negating the need for the transfer from the metal substrate. This technique is based on metal-induced crystallization of amorphous carbon (a-C) to graphene, and involves an ultra-thin metal layer that is less than 10 nm in thickness. Rapid annealing of a bilayer of a-C and metal deposited on the surface leads to the formation of graphene film, and to subsequent breaking-up of the thin metal layer underneath the film, thus resulting in the formation of a graphene–metal hybrid film which is both transparent and electrically conducting.

Theoretical and experimental study of nanopore drilling by a focused electron beam in transmission electron microscopy.

Sub-10 nm nanopores drilled by a focused electron beam in a transmission electron microscope are widely used in solid-state nanopore devices for DNA translocation. However, there still remains much controversy surrounding the drilling mechanism. In order to explain the drilling of nanopores by electrons, we undertook a theoretical consideration of the energy transfer from the fast electrons to the solid through such mechanisms as elastic and inelastic scattering.

Sub-10-nm nanochannels by self-sealing and self-limiting atomic layer deposition.

We report on a novel fabrication method of a nanochannel ionic field effect transistor (IFET) structure with sub-10-nm dimensions. A self-sealing and self-limiting atomic layer deposition (ALD) facilitates the fabrication of lateral type nanochannels smaller than the e-beam or optical lithographic limits. Using highly conformal ALD film structures, including TiO(2), TiO(2)/TiN, and Al(2)O(3)/Ru, we have fabricated lateral sub-10-nm nanochannels with good control over channel diameter.