1,030 results match your criteria: "Advanced Institute of Technology[Affiliation]"

Color arrestor pixels for high-fidelity, high-sensitivity imaging sensors.

Nanophotonics

July 2024

Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea.

Silicon is the dominant material in complementary metal-oxide-semiconductor (CMOS) imaging devices because of its outstanding electrical and optical properties, well-established fabrication methods, and abundance in nature. However, with the ongoing trend toward electronic miniaturization, which demands smaller pixel sizes in CMOS image sensors, issues, such as crosstalk and reduced optical efficiency, have become critical. These problems stem from the intrinsic properties of Si, particularly its low absorption in the long wavelength range of the visible spectrum, which makes it difficult to devise effective solutions unless the material itself is changed.

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  • Photo-induced force microscopy (PiFM) is a high-resolution imaging technique that utilizes photo-induced forces to enhance tip movement, allowing for detailed nanoscale spectroscopic imaging.
  • This review covers the complexities of PiFM, including the influences of both local dipole interactions and thermal expansion, and distinguishes between far-field and near-field effects.
  • The article serves as a comprehensive guide for beginners, combining theoretical insights with practical examples that span from basic concepts to more advanced topics in the field.
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Confinement of reactants within nanoscale spaces of low-dimensional materials has been shown to provide reorientation of strained reactants or stabilization of unstable reactants for synthesis of molecules and tuning of chemical reactivity. While few studies have reported chemistry within zero-dimensional pores and one-dimensional nanotubes, organic reactions in confined spaces between two-dimensional materials have yet to be explored. Here, we demonstrate that reactants confined between atomically thin sheets of graphene or hexagonal boron nitride experience pressures as high as 7 gigapascal, which allows the propagation of solvent-free organic reactions that ordinarily do not occur under standard conditions.

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Structural imperfections can be a promising testbed to engineer the symmetries and topological states of solid-state platforms. Here, we present direct evidence of hierarchical transitions of zero- (0D) and one-dimensional (1D) topological states in symmetry-enforced grain boundaries (GB) in 1T'-MoTe. Using a scanning tunneling microscope tip press-and-pulse procedure, we construct two distinct types of GBs, which are differentiated by the underlying symmorphic and nonsymmorphic symmetries.

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Chiral Damping of Magnons.

Phys Rev Lett

October 2024

Department of Electrical and Computer Engineering, National University of Singapore, 117583, Singapore.

Chiral magnets have garnered significant interest due to the emergence of unique phenomena prohibited in inversion-symmetric magnets. While the equilibrium characteristics of chiral magnets have been extensively explored through the Dzyaloshinskii-Moriya interaction (DMI), nonequilibrium properties like magnetic damping have received comparatively less attention. We present the inaugural direct observation of chiral damping through Brillouin light scattering (BLS) spectroscopy.

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Ovonic threshold switching (OTS) selectors based on amorphous chalcogenides can revolutionize 3D memory technology owing to their self-selecting memory (SSM) behavior. However, the complex mechanism governing the memory writing operation limits compositional and device optimization. This study investigates the mechanism behind the polarity-dependent threshold voltage shift (ΔV) through theoretical and experimental analyses.

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Modern graphics processing units (GPUs) provide an unprecedented level of computing power. In this study, we present a high-performance, multi-GPU implementation of the analytical nuclear gradient for Kohn-Sham time-dependent density functional theory (TDDFT), employing the Tamm-Dancoff approximation (TDA) and Gaussian-type atomic orbitals as basis functions. We discuss GPU-efficient algorithms for the derivatives of electron repulsion integrals and exchange-correlation functionals within the range-separated scheme.

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Visual interpretation of deep learning model in ECG classification: A comprehensive evaluation of feature attribution methods.

Comput Biol Med

November 2024

Department of Intelligence and Information, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea; Interdisciplinary Program in Artificial Intelligence, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea. Electronic address:

Feature attribution methods can visually highlight specific input regions containing influential aspects affecting a deep learning model's prediction. Recently, the use of feature attribution methods in electrocardiogram (ECG) classification has been sharply increasing, as they assist clinicians in understanding the model's decision-making process and assessing the model's reliability. However, a careful study to identify suitable methods for ECG datasets has been lacking, leading researchers to select methods without a thorough understanding of their appropriateness.

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  • The study focuses on the growing significance of atomic layer deposition (ALD) technology in semiconductor device miniaturization, highlighting the need for low-melting-point precursors for efficient processing.
  • Researchers created a comprehensive database containing melting point data for 1,845 organic metal compounds (OMCs), including important structural information, by extracting data from chemical vendor sources and scientific papers using natural language processing.
  • The developed database aims to facilitate quicker and more cost-effective identification of suitable ALD precursors, which is essential for advancing the semiconductor industry, despite the moderate performance of a neural network model used for melting point predictions.
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Surfactants can be used as nanoparticle stabilizing agents. However, since synthetic surfactants are not economically viable and environmentally friendly, biosurfactants are emerging as a green alternative for the synthesis and stabilization of nanoparticles. Nanoparticles have been applied in several areas of industry, such as the production of biomedical and therapeutic components, packaging coating, solar energy generation and transmission and distribution of electrical energy, among others.

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  • Ferroelectric HfO-based thin films are being researched for their potential in advanced electronic devices, but understanding their ferroelectric properties at the nanoscale remains a challenge due to their complex structures.
  • Recent studies using electron microscopy techniques have detailed the in-plane domain structures of Y:HfO films, revealing how their unique grain boundaries and phases contribute to their ferroelectricity.
  • Key findings show that specific orientations and patterns within the grain structures enhance polarization, and the behavior of domain walls affects the overall ferroelectric performance depending on their alignment and thickness of the films.
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Topological van der Waals Contact for Two-Dimensional Semiconductors.

ACS Nano

September 2024

Department of Materials Science and Engineering and Department of Energy Systems Research, Ajou University, Suwon 16499, Korea.

The relentless miniaturization inherent in complementary metal-oxide semiconductor technology has created challenges at the interface of two-dimensional (2D) materials and metal electrodes. These challenges, predominantly stemming from metal-induced gap states (MIGS) and Schottky barrier heights (SBHs), critically impede device performance. This work introduces an innovative implementation of damage-free SbTe topological van der Waals (T-vdW) contacts, representing an ultimate contact electrode for 2D materials.

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A critical bottleneck toward all-solid-state batteries lies in how the solid(electrode)-solid(electrolyte) interface is fabricated and maintained over repeated cycles. Conventional composite cathodes, with crystallographically distinct electrode/electrolyte interfaces of random particles, create complexities with varying (electro)chemical compatibilities. To address this, we employ an epitaxial model system where the crystal orientations of cathode and solid electrolyte are precisely controlled, and probe the interfaces in real-time during co-sintering by in situ electron microscopy.

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High dielectric constant () materials have been investigated to improve the performance of dynamic random access memory (DRAM) capacitors. However, the conventional binary oxides have reached their fundamental limit of < 100. In this study, we investigated alternative ternary oxides, SrTiO (STO) and (Ba,Sr)TiO (BSTO), which were epitaxially grown on SrRuO (SRO) using atomic layer deposition (ALD).

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In this study, a multiple-resonance (MR) core structure is developed with a spin-flip-restricted emission mechanism based on a fused indolo[3,2,1-jk]carbazole (ICz) framework as emitters to improve the lifetime of blue organic light-emitting diodes. The molecular skeleton modulation approach applied to the conjugated π-system effectively stabilizes the triplet energy of the fused ICz emitters and narrows the full-width-at-half maximum (<20 nm). In addition, the emitters exhibit higher exciton stability than conventional boron-based MR emitters.

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This study explores the optimal morphology of photochemical hydrogen evolution catalysts in a one-dimensional system. Systematic engineering of metal tips on precisely defined CdSe@CdS dot-in-rods is conducted to exert control over morphology, composition, and both factors. The outcome yields an optimized configuration, a Au-Pt core-shell structure with a rough Pt surface (Au@r-Pt), which exhibits a remarkable fivefold increase in quantum efficiency, reaching 86 % at 455 nm and superior hydrogen evolution rates under visible and AM1.

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Strongly polarized color conversion of isotropic colloidal quantum dots coupled to fano resonances.

Nanoscale Horiz

September 2024

Department of Electrical and Electronics Engineering, Department of Physics, UNAM--Institute of Materials Science and Nanotechnology and the National Nanotechnology Research Center, Bilkent University, Ankara, 06800, Turkey.

Colloidal quantum dots (QDs) offer high color purity essential to high-quality liquid crystal displays (LCDs), which enables unprecedented levels of color enrichment in LCD-TVs today. However, for LCDs requiring polarized backplane illumination in operation, highly polarized light generation using inherently isotropic QDs remains a fundamental challenge. Here, we show strongly polarized color conversion of isotropic QDs coupled to Fano resonances of v-grooved surfaces compatible with surface-normal LED illumination for next-generation QD-TVs.

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Article Synopsis
  • Iridium(III) organometallic complexes play a crucial role in the development of organic light-emitting diodes (OLEDs), but the link between their structure and light-emitting efficiency is not fully understood.*
  • Experimental and theoretical studies reveal that two similar iridium complexes, Red-pq and Red-piq, have different properties due to variations in the arrangement of their ligands, which affects their excited state geometry and quantum efficiency.*
  • The study finds that the greater geometric distortion in the Red-piq complex leads to reduced nonradiative decay, resulting in a higher quantum yield compared to Red-pq, thus highlighting how minor structural differences can impact performance in OLED applications.*
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  • The paper introduces a fine dust detection system that utilizes surface acoustic wave (SAW) sensors, which change their resonance points when exposed to fine dust.
  • The system includes two channels—a sensing channel and a reference channel—each equipped with a SAW oscillator and a 20-bit asynchronous counter to measure frequency differences.
  • The proposed circuit demonstrates a high frequency resolution of 0.95 parts per million (ppm) while operating at 460 MHz and was fabricated using a TSMC 130 nm CMOS process.
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The resolution of Si complementary metal-oxide-semiconductor field-effect transistor (C-MOSFET) image sensors (CISs) has been intensively enhanced to follow the technological revolution of smartphones, AI devices, autonomous cars, robots, and drones, approaching the physical and material limits of a resolution increase in conventional Si CISs because of the low quantum efficiency (i.e., ~40%) and aperture ratio (i.

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Understanding the saturated vapor pressure () is vital for evaluating atomic layer deposition (ALD) precursors, as it directly influences the ALD temperature window and, by extension, the processability of compounds. The early estimation of vapor pressure ranges is crucial during the initial stages of novel precursor design, reducing the reliance on empirical synthesis or experimentation. However, predicting vapor pressure through computer simulations is often impeded by the scarcity of suitable empirical force fields for molecular dynamics simulations.

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The primary challenge facing silicon-based electronics, crucial for modern technological progress, is difficulty in dimensional scaling. This stems from a severe deterioration of transistor performance due to carrier scattering when silicon thickness is reduced below a few nanometres. Atomically thin two-dimensional (2D) semiconductors still maintain their electrical characteristics even at sub-nanometre scales and offer the potential for monolithic three-dimensional (3D) integration.

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  • A new method was created to combine alkynylphenols with epoxides and elemental sulfur or selenium using a copper catalyst, resulting in a unique 3-chalcogen-benzofuran structure.
  • This process operates as a domino reaction, meaning it occurs in one go without needing to isolate or purify intermediates.
  • The method works well at room temperature, allowing for various sensitive functional groups and producing good yields of chalcogenation derivatives.
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