Dye adsorption is one of the most time-consuming processes in the fabrication of dye-sensitized solar cells (DSSCs), typically requiring approximately 24 h at room temperature. In this study, the effect of adsorption temperature and time on photovoltaic performance of DSSCs was investigated in order to reduce processing time and improve device productivity. Nanoporous TiO₂ photoelectrodes were immersed in N719 dye solution at 60°C for 3 h, 10 h, 17 h, and 24 h, and their performance was compared with that of cells sensitized at room temperature for 24 h. Photovoltaic characterization under AM 1.5 illumination showed that DSSCs sensitized at 60°C exhibited improved performance compared to those sensitized at room temperature. The device sensitized at 60°C for 3 h showed comparable or higher conversion efficiency than the reference cell sensitized for 24 h at room temperature. The improvement in device performance is attributed to enhanced dye adsorption kinetics resulting from increased reaction rate between the carboxyl groups of N719 dye molecules and hydroxyl groups on the TiO₂ surface. Electrochemical impedance spectroscopy analysis revealed reduced recombination resistance at the TiO₂/dye/electrolyte interface for cells sensitized at elevated temperature. UV–Vis absorption analysis confirmed increased dye loading on the TiO₂ surface for the 60°C condition. These results demonstrate that elevated temperature dye adsorption significantly reduces processing time while maintaining photovoltaic performance, providing an effective strategy for improving manufacturing efficiency of DSSCs.

The direct utilization of steelmaking by-product gases in solid oxide fuel cells (SOFCs) offers a promising pathway to improve energy efficiency and reduce carbon emissions in the steel industry. In this study, a Sr-deficient and Ni-doped double perovskite oxide, Sr_1.95Fe_1.35Ni_0.15Mo_0.5O_6-δ (SFNM), was investigated as an anode material for direct Linz-Donawitz converter gas (LDG)-fueled SOFCs. A single-phase double perovskite structure was successfully obtained after calcination at 1,200°C for 12 h, while exsolved metallic Ni nanoparticles were generated on the SFNM surface after reduction at 800°C. Electrochemical performance was evaluated using H₂, simulated-LDG, and CO/CO₂ (85:15) fuels at 800°C. The maximum power densities achieved were 1.23, 0.70, and 0.40 W cm^-2 for H₂, simulated-LDG, and CO/CO₂ fuels, respectively. Although CO-containing fuels exhibited lower opencircuit voltages and power outputs than H₂, the SFNM anode maintained stable operation and appreciable performance under direct simulated-LDG utilization. Impedance analysis revealed that the increased polarization resistance in simulated-LDG and CO/CO₂ atmospheres was mainly associated with fuel adsorption/desorption and gas diffusion, while interfacial charge-transfer resistance remained relatively small. The superior performance obtained with simulated-LDG compared to the CO/CO₂ mixture was attributed to the presence of a small amount of H₂, which facilitated anode reaction kinetics. These results demonstrate that SFNM is a promising mixed ionic-electronic conductor anode for the direct electrochemical conversion of CO-rich steelmaking by-product gases into electricity.

This paper reviews the energy yield enhancement characteristics of bifacial photovoltaic systems combined with solar tracking, focusing on their performance relative to conventional monofacial fixed-tilt configurations. The fundamental mechanisms of yield improvement are summarized, highlighting the largely additive contributions of solar tracking, which increases front-side irradiance, and bifacial modules, which utilize rear-side reflected and diffuse radiation. Reported results from previous studies indicate that bifacial systems with single-axis tracking typically achieve 25–35% higher annual energy yield compared with standard monofacial fixed-tilt systems, with variations depending on environmental and design conditions. Key design and environmental considerations influencing system performance are discussed to provide practical insights for the application of bifacial tracking systems in utilityscale photovoltaic installations.

This paper proposes a circular sequential lighting control method to reduce current imbalance and luminance deviation among multiple LED modules in AC-powered LED lighting systems. Conventional fixed-sequence lighting control repeatedly prioritizes the same LED modules in every rectified voltage cycle, which leads to unequal current distribution, luminance non-uniformity, and the accelerated degradation of specific modules during long-term operation. To address these limitations, a circular sequential lighting strategy is introduced, in which the lighting order is cyclically rotated at every rectified cycle, ensuring that all LED modules experience equal lighting opportunities. A prototype AC-LED lighting system consisting of four series-connected LED modules was implemented and experimentally evaluated. The results demonstrate that, while the conventional fixed-sequence method produces a maximum average current deviation of up to 1.6 mA among modules, the proposed method equalizes the average current across all modules to approximately 17.1 mA. Furthermore, the flicker index remains at 0.13, which is comparable to that of the conventional method, indicating that luminance uniformity is improved without degradation of optical performance. The proposed circular sequential lighting control effectively distributes electrical stress, enhances luminance uniformity, and improves long-term reliability, making it a practical and efficient solution for high-quality AC-LED lighting applications.

The potential of replacing crosslinked polyethylene (XLPE) with an eco-friendly alternative, polypropylene (PP), as insulating material is investigated for overhead power distribution lines. Although XLPE exhibits excellent electrical and mechanical properties, the byproducts generated during crosslinking pose environmental challenges. PP is a viable alternative because of recyclability and absence of byproducts during crosslinking. This study evaluated alternating current (AC) breakdown strength, contact angle, and tracking resistance of two commercially available XLPE samples and three types of PP (PP1, PP2, PP3) with varying additive content. AC breakdown strength, analyzed using the Weibull distribution, facilitated relative comparison of insulation performance. PP2 exhibited scale parameters comparable to or exceeding those of XLPE. Contact angles exceeding 90° displayed hydrophobicity across all samples. To address pass/fail evaluation limitations, arcing images from tracking tests were analyzed using the box-counting method for fractal dimension analysis. Fractal dimensions increased with arcing extent, and complexity increased with test duration. Tracking resistance performance order was PP3, PP1, CC, PP2, OC which was attributed to enhanced heat dissipation properties of filler additives. The proposed quantitative method for comparing tracking resistance through fractal dimension analysis, explored the feasibility of using PP insulating materials in overhead power distribution lines.

Electrochemical water splitting has emerged as a pivotal technology for green hydrogen production, offering a viable pathway toward a sustainable energy future. Among various electrolysis systems, Anion exchange membrane water electrolysis is particularly noteworthy as a cost-effective solution capable of operating under the fluctuating power inputs typical of renewable energy sources. However, the overall efficiency of water splitting is fundamentally limited by the oxygen evolution reaction, which exhibits sluggish kinetics compared to the hydrogen evolution reaction. While IrO₂ and RuO₂ serve as current benchmarks, their scarcity and high cost necessitate the development of earth-abundant alternatives. This review provides a comprehensive overview of fundamental OER mechanisms including the adsorbate evolution mechanism, lattice oxygen mechanism, and oxide path mechanism while highlighting how new pathways can circumvent traditional scaling relations. We discuss recent advancements in transition metal-based electrocatalysts, encompassing oxides, hydroxides, chalcogenides, phosphides, nitrides, and carbides, with a focus on innovative design strategies such as defect engineering, heteroatom doping, and heterostructure construction. This paper concludes by addressing current challenges and offering perspectives on future directions for the development of highly efficient and economically viable oxygen evolution electrocatalysts for large-scale applications.

Breakdown strength is an essential parameter for evaluating the electrical performance and degradation behavior of cable insulation and IEC 60243 also emphasizes its importance for detecting changes in insulation characteristics due to aging. However, the current IEC standards are mainly limited to specifying electrode configurations and test voltage conditions for breakdown tests, while the influence of insulating oil, is not clearly addressed. In this study, the breakdown strength of a 66 kV wet-type submarine cable was experimentally evaluated using insulating oils with different kinematic viscosities of 10, 100, 500, and 1,000 cSt in order to achieve reliable and reproducible breakdown measurements. The experimental results show that the measured breakdown strength decreases by up to approximately 20% depending on the oil viscosity. This indicates that the viscosity of the insulating oil has a significant influence on the measured breakdown strength during breakdown test. Therefore, it is necessary to perform breakdown strength measurements under identical test conditions, including the physical properties of the insulating oil, to ensure reliable comparison and accurate assessment of insulation performance and degradation characteristics.

This study investigates the effect of mask material and thickness on the silicon etching profile using a high-density plasma (HDP) etching system, aiming to reduce optical loss in silicon-based optical waveguides. As the mask thickness increased, the etching sidewall angle became steeper. An etching profile angle of 87° was obtained when tetraethyl orthosilicate (TEOS) was used as the mask material, while 80° was obtained for photoresist (PR). This is attributed to electron charging on the mask surface in the plasma. The charged mask modifies the distribution and strength of the electric field depending on its thickness, thereby affecting the trajectory of positive ions accelerated toward the substrate by the bias voltage. Furthermore, Plasma diagnostics using optical emission spectroscopy (OES) and surface composition analysis using field emission Auger electron spectroscopy (FE-AES) revealed that changes in the mask material also alter the reaction pathways and formation characteristics of active species and silicon by-products in the plasma. These results suggest that the mask material influences the overall plasma characteristics, including electron density and ion energy, and plays a critical role in the precise control of silicon etching profiles for high-performance optical device fabrication.

The growing demand for thinner, lighter, and more energy-efficient electronic systems has driven the development of acoustic technologies toward compact and flexible sound generation platforms. Despite significant progress, conventional electromagnetic speakers remain limited by bulky structures, energy losses, and poor compatibility with modern ultrathin devices. In this review, recent advancements in piezoelectric acoustic systems are presented, demonstrating a new generation of speakers capable of producing high-fidelity sound from ultra-slim, lightweight, and mechanically compliant designs. Through refined structural configurations and efficient electromechanical coupling, these piezoelectric exciters achieve strong acoustic output, fast response, and wide frequency operation while drastically reducing component thickness. These exciters also show their suitability for seamless integration into flexible displays, wearable devices, and automotive panels, offering enhanced spatial audio practicality and multifunctional operation, including demonstrative output and sensing. This advancement marks a step toward the convergence of acoustic, haptic, and interactive technologies, for the realization of sustainable and immersive humanmachine interfaces in future electronic and automotive systems.

To ensure high-voltage stability and thermal resistance of insulation paper used in transformers, this study evaluated the structural and electrical properties of four types of insulation paper samples fabricated using unbleached kraft pulp (UKP). The samples were prepared under controlled conditions with different freeness levels (300-700 ml). Tensile strength, dielectric constant, breakdown strength (dry and oil), volume resistivity, water absorption, and oil absorption were quantitatively measured. The sample with a beating degree of 300 exhibited the highest breakdown strength (53.85 kV/mm) and volume resistivity (1.49×10¹⁶ Ω·cm), whereas the samples with higher beating intensity showed improved fiber bonding and densification. These findings demonstrate the practical applicability of UKP-based insulation paper as a high-performance, eco-friendly insulating material for transformer systems, providing a scientific foundation for process optimization in insulation paper design.

Perovskite light-emitting diodes (PELEDs) are emerging as promising candidates for next-generation displays, thanks to their narrow full width at half maximum and low-cost solution processing capabilities. Blue PeLEDs are essential for achieving a full-color gamut; however, efficiency and stability challenges limit their practical use. A primary bottleneck arises from interfacial issues between the perovskite emissive and charge transport layers. This review summarizes the key interfacial challenges hindering the performance of blue PeLEDs and highlights recent advances in interfacial engineering strategies. By focusing on interfacial engineering between the hole-transport layer and perovskite, this review compares different strategies and outlines future directions for developing high-performance blue light-emitting devices.

Silicon carbide (SiC), with its wide bandgap and strong resistance to radiation and thermal conditions, is a promising material for ultraviolet (UV) photodetector applications under harsh environments. In this study, porous SiC thin films with thicknesses of 20, 50, and 80 nm were fabricated on 4H-SiC substrates using aerosol deposition (AD), which enables roomtemperature film formation. The device with a 50 nm-thick film exhibited the highest photoresponse under UV-C illumination (260 nm), achieving a maximum photo-to-dark current ratio (PDCR) of 205.2, a responsivity of 0.058 A/W, an external quantum efficiency (EQE) of 27.71%, and a specific detectivity (D*) of 7.9×10¹¹ Jones. These results are attributed to an optimized balance between photon absorption and carrier transport in the porous structure. The findings confirm the potential of ADfabricated porous SiC films for highly sensitive and scalable UV photodetector applications.

Silicon carbide (SiC) power devices are attracting increasing attention for high-voltage and high-efficiency applications due to their superior material properties. However, achieving an optimal trade-off between specific on-resistance (Ron,sp) and breakdown voltage (BV) remains a key design challenge in planar MOSFET structures. In this study, twodimensional TCAD simulations were conducted to investigate the impact of varying the doping concentrations of the P-well (from 3 × 10¹⁷ to 6 × 10¹⁷ cm^-3) and JFET regions (from 1 × 10¹⁶ to 7 × 1016 cm^-3) on the electrical characteristics of 2.4 kVclass planar SiC MOSFETs. To maintain comparable BV conditions for 2.4 kV operation, two groups with P-well doping concentrations of 4.5 × 10¹⁷ cm^-3 and 5.3 × 1017 cm^-3 were analyzed and compared. When the P-well and JFET doping concentrations were 4.5 × 10¹⁷ cm^-3 and 1.5 × 10¹⁶ cm^-3, respectively, the simulated Ron,sp and BV were 1.41 mΩ·cm² and 3,150 V. In contrast, with P-well and JFET doping concentrations of 5.3 × 10¹⁷ cm^-3 and 5.0 × 10¹⁶ cm^-3, the Ron,sp was reduced to 1.31 mΩ·cm² while the BV slightly increased to 3,200 V. Based on these results, an optimized device structure was proposed, demonstrating its potential for integration into high-voltage SiC-based power systems. This study provides practical design insights and is expected to contribute to the advancement of wide bandgap semiconductor technologies for next-generation power electronics.

With the advancement of the information society, the demand for highly integrated and multi-functional electronic devices is rapidly increasing. To meet these demands, high-performance transistors with low power consumption, high-speed operating, and mechanical flexibility are essential. Among various candidates, semiconducting single-walled carbon nanotubes (s-SWCNT)-based transistors, which exhibit intrinsically ambipolar characteristics, have emerged as promising components for CMOS-like circuits. In this study, s-SWCNT were selectively dispersed using rr-P3DDT, a thiophene-based conjugated polymer, and filed-effect transistors (FETs) were fabricated by inducting directional alignment for enhanced charge transport through an off-centered spin-coating process. The electrical characteristics of the fabricated s-SWCNT FETs were evaluated under various thermal annealing conditions (100℃, 150℃, 200℃, and 250℃). Off-centered spin-coated and high temperature annealed s- SWCNT FETs exhibited high field-effect mobilities over 5 cm²/Vs in both p-type and n-type operation, along with ideal Vshaped ambipolar transfer curves. These results indicate a significant enhancement in ambipolar performance due to efficient desorption of residual oxygen and water molecules in active channel via high temperature annealing. Furthermore, CMOS-like inverter circuits demonstrated an ideal inversion voltage (VIN = V_DD/2) and a high voltage gain of approximately 9.5. These findings highlight the potential of SWCNT-based materials for realizing next-generation flexible electronic circuits that combine high-performance, energy efficiency, and simplified solution-processing.

NTC (negative temperature coefficient) thermistors are semiconductor ceramics whose resistance decreases with increasing temperature, making them essential components in various temperature sensing applications. Typically, ceramic materials are sintered at high temperatures exceeding 1,150°C. However, in laminated devices incorporating internal electrodes, co-sintering can lead to cracking and mechanical failure due to mismatches in the thermal expansion coefficients between the ceramic layers and metal-based electrodes. Moreover, the use of noble metal electrodes increases production costs. To address these challenges, a low-temperature sintering approach is required. Previous studies have demonstrated that incorporating glass frit can reduce the sintering temperature of ceramics, although this often results in increased electrical resistance. In this study, NiMnCoO₄ (NMC) ceramics, as a representative NTC thermistor composition, were prepared with the addition of 10 wt% glass frit. To mitigate the resulting increase in resistivity, trace amounts (1 wt%) of various metal oxides, including CuO, ZnO, and MnO, were introduced. Among these, the addition of CuO notably decreased both the resistivity and B constant values. In contrast, MnO had little effect on resistivity, while ZnO led to an increase. With respect to the B25/85 constant, samples containing MnO and ZnO exhibited higher values than those without metal oxide additives. These findings indicate that the incorporation of 1 wt% CuO is effective in reducing the increased resistivity in NMC ceramics subjected to low-temperature sintering via glass frit addition.

Metal halide perovskite materials have emerged as promising candidates for next-generation optoelectronic applications owing to their outstanding optical properties and tunable emission characteristics. However, their practical application is hindered by poor environmental stability, especially under conditions of heat, moisture, and UV exposure, necessitating effective encapsulation strategies. This review summarizes recent progress in enhancing the environmental stability of perovskite nanocrystals through polymer matrix embedding, inorganic oxide encapsulation, and compositionally matched core-shell structures using homogenous perovskite derivatives. We discuss how polymers enhance the environmental and moisture stability of perovskite nanocrystals, how oxide-based shells (e.g., SiO₂, TiO₂) contribute to thermal robustness and barrier protection, and how homostructural core-shells provide lattice-matched defect passivation with improved long-term durability. A comprehensive understanding of the advantages and limitations of each encapsulation strategy, along with their rational integration, can accelerate the commercialization of perovskite-based technologies in various applications such as highcolor- purity displays, color conversion filters, and flexible optoelectronic devices.

The continuous and long-lasting monitoring of physiological signals induced from the human body is crucial for health monitoring, disease diagnosis, and treatment. In this study, we have reported the Seebeck effect-based flexible selfpowered temperature sensor which can convert the electric signals from lateral temperature difference. For demonstrating temperature sensor arrays, the p-type thermoelectric (TE) composite films were fabricated by dispersing the Bi_0.5Sb_1.5Te₃ (BST) powders inside poly-vinylidene fluoride matrix and subsequently attached to the patterned electrode foils. The inorganic BST powders-embedded TE composite films with activated area of 0.5 × 1 cm² harvest a maximum voltage of 1.7 mV, a maximum current of 5.6 mA, and an output power of 2.6 nW from the temperature gradient (ΔT) of 20 K. Finally, the fabricated selfpowered temperature sensor array well detected the pattern images of external thermal source of ΔT = 20 K. This study manifests flexible temperature sensor array which paves the way for further advancements in this field.

Conductive inks are essential for developing flexible and wearable electronic devices, where printability and electrical performance must be finely balanced. However, achieving high conductivity while minimizing costly silver filler content remains a key challenge in ink formulation. In this work, we demonstrate that a simple ball-milling process transforms spherical silver particles into platelet-shaped fillers, dramatically enhancing conductivity at equivalent filler loading. The resulting inks show a reduction in sheet resistance from ~180 Ω/□ to ~ 0.57 Ω/□ at 70 wt% filler content, with improved performance attributed to surface-to-surface contact between platelets. Moreover, we show that filler content influences not only electrical conductivity but also ink viscosity, with the 53.8 wt% formulation achieving a practical balance between conductivity, processability, and cost. This morphology- and composition-controlled ink design offers a scalable strategy for manufacturing high-performance, cost-effective conductive inks suitable for next-generation printed electronics.

With the expansion of offshore wind farms, research on power cables for delivering electricity from offshore to onshore has become increasingly important. In offshore wind farms, submarine cables are introduced and secured to the platform through J-tube conduits. During this process, the cables are exposed to three distinct thermal profiles: high temperatures in the upper section, temperature fluctuations due to water level changes in the middle section, and low temperatures in the seabed region. This study investigates the impact of thermal variations on the insulation performance of submarine cables. To analyze this effect, accelerated aging tests were conducted on both insulation specimens and actual cables. Additionally, dielectric breakdown tests were performed to quantitatively assess insulation degradation. Experimental results revealed that the insulation performance of the specimens exposed to periodic temperature fluctuations due to water level changes deteriorated by up to 7.5%. Based on these findings, the vulnerable sections of submarine cables in offshore wind farms were identified. Furthermore, this study emphasizes the necessity for monitoring and protective measures to mitigate insulation degradation in these critical regions.

The characteristics of each address discharge were investigated when the voltages of the scan and common electrodes were lowered simultaneously during an address period under the same address voltage conditions in an AC plasma display panel. It was confirmed that the delay time of address discharge shortened as the voltage decreased. However, the background light increased because the low scanning voltage generated more discharge between the electrodes of the upper and lower plates in the reset period. To lower the background light, a positive voltage was applied to the address electrode of the lower panel during the period when the rising ramp wave was applied, and a floating voltage was applied to the address electrode during the period when the falling ramp wave was applied during the reset period. As a result, the background light could be lowered by about 30%.

This review examines the principles, limitations, and recent advancements in elastic modulus measurement using nanoindentation. The importance of accurate contact area prediction is discussed, along with the Oliver-Pharr method and its limitations. The Continuous Stiffness Measurement (CSM) technique is presented as a significant improvement, allowing continuous measurement of mechanical properties throughout the indentation process. For ultra-thin films, the Li and Vlassak method, which incorporates Yu's solution and the concept of effective thickness, is highlighted as a means to correct for substrate effects. Recent developments in artificial neural network-based models for elastic modulus prediction are also explored. These advancements have greatly expanded the applicability of nanoindentation in semiconductor and MEMS device reliability assessment.

In parallel with the efforts to improve the device performance in modern integrated circuits, it is necessary to downscale their core components, field-effect transistors (FETs), generally gauged by their physical gate length. Upon such device scaling, the emergence of the short-channel effect impedes further scaling into the nanometer scale in the silicon VLSI (Very-Large-Scale-Integration) system. To address this issue, two-dimensional (2D) semiconductors, leveraging their atomically thin thickness and dangling-bond-free characteristics, are being highlighted as a material solution for future scaling technology without severe mobility degradation. Despite the expected ideal physical properties, 2D semiconductors have yet to realize their full potential owing to the limited development of integration technology. In this context, we survey and review the tailored van der Waals integration technologies for 2D FETs. In particular, we provide an in-depth study of both van der Waals integrated contact and dielectric methods along with an explanation of customized materials. In essence, this van der Waals integrationcentered approach will be a core strategy to implement the high-performance 2D transistors that meet the demand of FET miniaturization.

With the recent active development of laser-based weapons/monitoring/communication systems, there is a significant increase in the demand for improved performance of piezoelectric actuators, a key component of both deformable mirror (DM) and fast steering mirror (FSM) in the systems. The conventional polycrystalline piezoelectric ceramic actuators have limitations in improving their characteristics, so the ultrahigh strain PMN-PZT piezoelectric single crystal multilayer actuators have been developed. In this study, the basic experimental methods were developed to evaluate their stability as well as reliability. The limitations of deformation and applied voltage were confirmed through the breakdown voltage test, and the degree of stability was confirmed through the hammering test. In this study, the breakdown voltage test and the hammering test were confirmed to be effective methods to evaluate their stability as well as reliability. Through these studies, the next-generation PMN-PZT piezoelectric single-crystal multilayer actuator is expected to be applied to various piezoelectric application fields by securing reliability as well as excellent piezoelectric properties.

Perovskite, which follows the chemical formula ABX3 and exhibits an octahedral structure, is primarily a hybrid of organic and inorganic materials. It can be broadly categorized into three types based on dimensionality: 0D nanocrystals, quasi- 2D, and 3D bulk structures. As a result, it is gaining attention as a next-generation optoelectronic material for applications in light-emitting devices, solar cells, and sensors. This paper provides insights into dimension of perovskites, their respective synthesis methods, and current research trends, thereby offering prospects for advancements in the study of next-generation optoelectronic materials.

We propose a real-time information propagation arithmetic neural network (PANN) that minimizes the loss of power generation output of the system in the event of sudden changes in the module due to strong external typhoons or earthquakes at the solar power generation facility site. In addition, we propose a new double-sided module reflector that can reduce the local loss of power generation efficiency of the single-sided module reflector that is currently widely distributed, as well as the environmental pollution and inconvenience of maintenance work of the existing double-sided module. We present a computational network that can detect the faulty solar panel in real-time by checking the fault status of the installed solar panel and using a real-time computation method through a node-to-node diffusion method. In particular, this method recognizes the power loss part due to sudden changes in the module in real time and can take emergency measures for various nonlinear field facilities through a neural structure that finds the optimal distance up, down, left, and right. To confirm the characteristics of the loss reduction control of the field facility, we confirmed that the system was configured as a 7-degree-of-freedom control model using the PANN neural network learning structure method and improved the power generation output. PANN (Propagation Arithmetic Neural Networks) and various module systems are proposed for the real-time recovery of faulty solar panels and improving module system efficiency.

Smart electronic skin (E-skin) is an emerging technology that integrates electronic devices with human skin, enhancing human-machine interactions. One critical challenge in its development is effective thermal management to ensure device reliability, longevity, and user comfort. This review highlights passive cooling techniques - thermal conduction, convection, radiation, and phase-change materials - as key strategies to address this challenge without additional power consumption. These integrated mechanisms have demonstrated the ability to efficiently dissipate heat, preventing thermal buildup and maintaining optimal performance in E-skin devices. Recent advancements indicate that combining these methods can significantly enhance the thermal management of flexible electronics. Future research should focus on refining these materials and techniques to overcome challenges related to cost, durability, and environmental stability, thereby advancing the practical application of E-skin technology.

Hazardous gas leakage incidents rank among the most serious safety accidents, leading to significant loss of life, extensive property damage, and severe environmental pollution. This paper describes an innovative IoT-based Assembly Double Pipe System (IADPS) designed for the prevention, early detection, and automated isolation of toxic gas leaks. The proposed system features a double-layered pipe design, with nitrogen charged between the inner and outer pipes, and gas detectors installed at strategic locations. This configuration is intended to prevent pipe corrosion, suppress ignition caused by escaping gas, and facilitate the early detection of gas leaks, thereby mitigating the risk of safety accidents. Furthermore, the system includes a comprehensive real-time monitoring system for pipe integrity and gas leakage, as well as an automated gas leakage detection and isolation system to quickly respond to any incidents.

As the operating environment in semiconductor processes becomes demanding, research is being conducted to manufacture dense alumina substrates without defects after sintering to ensure high durability of electrostatic chucks, which are critical components in semiconductor equipment. Therefore, in this study, in order to manufacture green sheets with a high filling ratio for implementing a high-density substrate, alumina powders with average particle sizes of 2.07 μm (L) and 0.37 μm (S) were mixed in ratios of 9:1, 8:2, 7:3, and 6:4, respectively, and green sheets were manufactured and the filling ratio and sintering behavior were observed. Green sheets were fabricated by preparing a slurry using organic materials in Al₂O₃ powders of different particle sizes. The packing density of the green sheet mixed with L and S alumina powders with different average particle sizes in a ratio of 7:3 before and after binder burn-out showed the highest values of 3.19 g/cm³ and 2.87 g/cm³, respectively. As a result of observing the sintered density based on the mixing ratio of alumina powders revealed that the alumina sheet mixed at a 6:4 ratio of L and S powders, sintered at 1,700℃, exhibited the best sintering characteristics with a density of 3.96 g/cm³.

Department of Electric Materials Engineering, Kwangwoon University, Seoul 01897, Korea (Received June 13, 2024; Revised July 8, 2024; Accepted July 10, 2024) Abstract: Wide bandgap (WBG) devices, especially SiC, are gaining traction as materials for high-power EV conversion devices due to their superior efficiency and switching capabilities compared to Si-based power devices. SiC allows for high power, high temperature, and high frequency applications because of its outstanding thermal conductivity, saturation velocity, and dielectric breakdown field. SiC-based MPS diodes combine the advantages of SiC-based SBDs and PiN diodes, allowing high-frequency switching operation with low leakage currents under high voltage conditions. However, MPS diodes exhibit snapback phenomena influenced by the P⁺ region’s size, necessitating optimization. A TCAD simulation studied the impact of the P+ region’s depth and width on MPS diode performance. Increasing the P⁺ width raised the On-specific resistance (R_on,sp) and lowered the maximum voltage during snapback (V_snap). Increasing the depth decreased both Breakdown voltage (BV) and V_snap. A trade-off between the semiconductor performance index BFOM and V_snap was identified, leading to optimized dimensions. The optimized MPS diode shows a low V_snap of about 3.89 V and a high BFOM of 1.72 GW·㎠, highlighting its potential as a next-generation high-performance power conversion device.

Gallium oxide (Ga₂O₃) is emerging as a next-generation power semiconductor material due to its excellent electrical properties, including an ultra-wide bandgap of approximately 4.8 eV and a breakdown electric field of about 7 MV/cm. However, its low thermal conductivity of around 0.13 W/cmK presents significant challenges to the performance and reliability of Ga₂O₃- based devices. In this study, we employed the Silvaco TCAD simulator to analyze the thermal and electrical characteristics of Ga₂O₃ Schottky barrier diodes (SBDs) with heat sinks of varying thermal conductivities. The results demonstrate that heat sinks with higher thermal conductivity effectively mitigate the temperature rise in the device, leading to an increase in current density. The limitation in heat dissipation due to parasitic on-state resistance not only affects device performance but also impacts longterm reliability. Therefore, this study contributes to the development of effective thermal management strategies for Ga₂O₃-based power semiconductors.