The dielectric and piezoelectric properties of the ferroelectric BaTiO₃ were measured and analyzed using both strong and weak electric field conditions. To measure the electric field induced polarizations and strains, a high voltage source and the measuring circuit were used and the dielectric constants were measured with an impedance analyzer. The spontaneous polarization of BaTiO₃ at room temperature was calculated as 17 μC/cm² based on the lattice structure and internal ion location, which is in good agreement with the experimental results. The polarization and strain hysteresis curve according to the electric field were analyzed in terms of lattice structure and ion position. The magnitude of remanent polarization is proportional to the offset distance of Ti⁴⁺ ion from the lattice center. The magnitude of dielectric permittivity is proportional to the degree to which Ti⁴⁺ ion can move freely inside the lattice. The magnitude of piezoelectric constant d₃₃ is proportional to how much Ti⁴⁺ ion distorts the lattice as it moves inside the lattice.

Organic solar cells based on bulk heterojunction (BHJ) structures have attracted considerable attention because of their low fabrication cost, mechanical flexibility, and compatibility with solution-processing techniques. In BHJ organic photovoltaic devices, nanoscale morphology and crystallinity of the photoactive layer critically influence photovoltaic performance. In this study, the effects of solvent selection and thermal annealing on crystallization evolution and photovoltaic characteristics of P3HT:PCBM organic solar cells were systematically investigated. Three different solvents, including toluene, chlorobenzene (CB), and dichlorobenzene (DCB), were employed for active-layer fabrication, followed by post-thermal annealing treatment. UV–visible absorption spectroscopy revealed solvent-dependent differences in molecular ordering and intermolecular π–π interactions within the active layer. X-ray diffraction analysis confirmed that thermal annealing significantly enhanced crystallinity and lamellar ordering of P3HT domains, particularly for CB-processed films. Electrical characterization demonstrated that solvent evaporation behavior strongly affects photovoltaic performance. Among the investigated devices, the thermally annealed CB-processed device exhibited the highest power conversion efficiency of 1.83% with an enhanced short-circuit current density of 7.057 mA cm⁻². The improved device performance is attributed to optimized crystallization behavior and balanced nanoscale phase separation induced by the moderate evaporation characteristics of CB. In contrast, although DCB-assisted films exhibited relatively strong optical absorption and enhanced crystallinity, excessively slow solvent evaporation likely induced excessive aggregation and coarse phase separation, limiting efficient photovoltaic characteristics. These results demonstrate that solvent engineering combined with thermal annealing is an effective strategy for controlling morphology evolution and crystallization behavior in P3HT:PCBM bulk heterojunction solar cells.

Bismuth layer-structured ferroelectrics with high Curie temperatures have recently attracted significant attention as promising candidates for high-temperature piezoelectric applications. However, the conventional solid-state reaction method entails high-temperature processing that induces bismuth volatilization, thereby degrading device reliability. In this study, we employed a co-precipitation method enabling atomic-level mixing to significantly lower the synthesis temperature of Nb/Tadoped Bi₄Ti₃O₁₂ ceramics compared to the solid-state reaction method. Experimental results demonstrated that the coprecipitation method yielded a pure single phase at 600℃ without intermediate phases. Furthermore, the synthesized nanopowders, with an average size of 100 nm, lowered the onset temperature of sintering shrinkage to 650℃, approximately 200℃ lower than that of the solid-state counterpart. The low-temperature synthesis process proposed in this work is expected to contribute to the performance enhancement of high-temperature piezoelectric devices by effectively suppressing bismuth volatilization and ensuring compositional stability.

Flexible and wearable electronics, which require stable operation under mechanical deformation, are increasingly utilizing Eutectic Gallium-Indium (EGaIn) for their conductive components. This study presents a systematic approach to fabricating highly reliable, deformable electrodes via a direct-ink-writing (DIW) 3D printing process using EGaIn as the functional ink. We conducted a thorough optimization of key printing parameters, specifically the extrusion pressure and printing speed, to achieve stable and uniform conductive lines. Through this optimization, we successfully established an optimal process window, achieving a stable line width of approximately 130 μm at an extrusion pressure of 300 kPa and a printing speed of 16 mm/s. The fabricated flexible electrodes exhibited exceptional electromechanical stability, maintaining negligible resistance change (< 0.82%) both under severe bending (3 mm radius) and after 100 repetitive bending cycles. This work demonstrates that the 3D printing of EGaIn is a viable and effective method for creating robust, high-performance electrodes for the next generation of deformable and wearable electronic devices.

Multilayer ceramic capacitors (MLCCs) are essential for high-capacitance, miniaturized, and reliable electronic applications. This study examines the impact of layer stacking on the dielectric and electrical properties of MLCCs using a BaTiO₃-based dielectric with MgO, Mn₃O₄, Yb₂O₃, V₂O₅, and (BaCa)SiO₃ glass additives. MLCCs with 10 um-thick dielectric layers and varying Ni electrode layers (10, 30, 50, and 100 layers) were fabricated. The dielectric constant increases significantly up to 30 layers due to compressive stress and sintering densification but it becomes linear beyond 30 layers. Dissipation factor and ESR decrease with higher stacking due to improved sinterability, while breakdown voltage declines exponentially from defect accumulation and thermal stress. Insulation resistance decreases but stabilizes relative to capacitance. C-V results show stress-induced polarization suppression, which reduces the dielectric constant under high voltage. Optimized stacking and sintering conditions are crucial for MIL-PRF-32535 compliant MLCC designs.

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.

This review addresses the development trends of dielectric ceramics, the key material for Multilayer Ceramic Capacitors (MLCCs), which are essential components in high-performance electronic devices. Traditional MLCCs have employed BaTiO₃ (BT)-based dielectrics to achieve high dielectric constant and low resistance. By minimizing oxygen vacancies and suppressing grain growth in BT materials, the temperature and voltage stability of MLCCs have been improved, leading to the development of MLCCs with diverse properties. However, the maximum dielectric constant of approximately 3000 in BT materials poses a limitation in overcoming the trade-off between rated voltage and capacitance density. Therefore, ultra-high permittivity dielectric materials have gained attention to meet the requirements of ultra-high-performance MLCCs, and ongoing research focuses on enhancing the temperature and frequency stability of these materials. This review analyzes the characteristics and limitations of conventional BT materials and explores recent research trends and future potential in developing new MLCCs based on ultra-high dielectric constant materials.

In this study, the effect of thickness on the Sn-doped β-Ga₂O₃ thin films was investigated. β-Ga₂O₃ is a next-generation material for power semiconductors and optoelectronics owing to its remarkable properties, such as an ultra-wide bandgap, excellent thermal and chemical stability, and large breakdown voltage. However, its inherently low conductivity can be limiting in applications that require high conductivity; therefore, improving the conductivity of β-Ga₂O₃ is important. In this study, Sn-doped β-Ga₂O₃ thin films with various thicknesses were deposited on β-Ga₂O₃ substrates. All the fabricated samples exhibited β-phase with a uniform and dense surface and transmittance of above 80% in the visible region. In particular, the 100 nm samples showed the highest carrier concentration and mobility and the lowest resistivity. Thus, these findings are expected to play an important role in improving the performance of devices by controlling the thickness of thin films.

Micro light-emitting diodes (μLEDs) have been utilized in various fields such as displays, and smart devices, due to their superior stabilities. Since the applications of the μLEDs have been extended to medical devices and wearable sensors, excellent optical properties and uniformity of the μLEDs are important. Hence, several researchers have investigated to enhance the optical efficiency of the μLEDs through micro/nano lens. However, the reported methods for realizing the micro/nano lens have some drawbacks such as complex and high-cost manufacturing processes. Herein, we developed μLEDs with 3D-printed hydrogel microlenses. The printed hydrogel had high transparency and excellent adhesive strength, allowing it to attach onto top surface of the μLEDs without any additional adhesives. Microscale printing technology using a 3D printer achieved quick and fine printing in desired shapes and arrangements, showing the possibility of mass production. The 3D-printed microlens can be applied to improve not only the optical properties of μLEDs but also other optical devices.

This study proposes an innovative methodology for developing flexible printed circuit boards (FPCBs) capable of conforming to three-dimensional shapes, meeting the increasing demand for electronic circuits in diverse and complex product designs. By integrating a traditional flat plate-based fabrication process with a subsequent three-dimensional thermal deformation technique, we have successfully demonstrated an FPCB that maintains stable electrical characteristics despite significant shape deformations. Using a modified polyimide substrate along with Ag flake-based conductive ink, we identified optimized process variables that enable substrate thermal deformation at lower temperatures (~130℃) and enhance the stretchability of the conductive ink (ε ~30%). The application of this novel FPCB in a prototype 3D-shaped sensor device, incorporating photosensors and temperature sensors, illustrates its potential for creating multifunctional, shape-adaptable electronic devices. The sensor can detect external light sources and measure ambient temperature, demonstrating stable operation even after transitioning from a planar to a three-dimensional configuration. This research lays the foundation for next-generation FPCBs that can be seamlessly integrated into various products, ushering in a new era of electronic device design and functionality.

In this study, KTN heterolayer thin films were fabricated by alternately stacking films of K(Ta_0.70Nb_0.30)O₃ and K(Ta_0.55Nb_0.45)O₃ synthesized using the sol-gel method. The sintering temperature and time were 750℃ and 1 hour, respectively. All specimens exhibited a polycrystalline pseudo-cubic crystal structure, with a lattice constant of approximately 0.398 nm. The average grain size was around 130~150 nm, indicating relatively uniform sizes regardless of the number of coatings. The average thickness of a single-coated film was approximately 70 nm. The phase transition temperature of the KTN heterolayer films was found to be approximately 8~12℃. Moreover, the 6-coated KTN heterolayer film displayed an excellent dielectric constant of about 11,000. As the number of coatings increased, and consequently the film thickness, the remanent polarization increased, while the coercive field decreased. The 6-coated KTN heterolayer film exhibited a remanent polarization and coercive field of 11.4 μC/cm² and 69.3 kV/cm at room temperature, respectively. ΔT showed the highest value at a temperature slightly above the Curie temperature, and for the 6-coated KTN heterolayer film, the ΔT and ΔT/ΔE were approximately 1.93 K and 0.128×10^-6 K·m/V around 40℃, respectively.

(La0.7Sr0.3)(Mn1-xFex)O3 (LSMFO) (x = 0.03, 0.06, 0.09, 0.12) precursor solution are prepared by sol-gel method. LSMFO thin films are fabricated by the spin-coating method on Pt/Ti/SiO2/Si substrate, and the sintering temperature and time are 800℃ and 1 hr, respectively. The average thickness of the 6-times coated LSMFO films is about 181 to 190 nm and average grain size is about 18 to 20 nm. As the amount of Fe added in the LSMFO thin film increased, the resistivity decreased, and the TCR and B25/65-value increased. Electrical resistivity, TCR and B25/65-value of the (La0.7Sr0.3)(Mn0.88Fe0.12)O3 thin film are 0.0136 mΩ-cm, 0.358%/℃, and 328 K at room temperature, respectively. The resistivity properties of LSMFO thin films matched well with Mott’s VRH model.

This reports the electrical properties of single-crystal β-gallium oxide (β-Ga₂O₃) vertical Schottky barrier diodes (SBDs) with a different guard ring structure. The vertical Schottky barrier diodes (V-SBDs) were fabricated with two types guard ring structures, one is with metal deposited on the Al₂O₃ passivation layer (film guard ring: FGR) and the other is with vias formed in the Al₂O₃ passivation layer to allow the metal to contact the Ga₂O₃ surface (metal guard ring: MGR). The forward current values of FGR and MGR V-SBD are 955 mA and 666 mA at 9 V, respectively, and the specific on-resistance (Ron,sp) is 5.9 mΩ·cm² and 29 mΩ·cm². The series resistance (Rs) in the nonlinear section extracted using Cheung’s formula was 6 Ω, 4.8 Ω for FGR V-SBD, 10.7 Ω, 6.7 Ω for MGR V-SBD, respectively, and the breakdown voltage was 528 V for FGR V-SBD and 358 V for MGR V-SBD. Degradation of electrical characteristics of the MGR V-SBD can be attributed to the increased reverse leakage current caused by the guard ring structure, and it is expected that the electrical performance can be improved by preventing premature leakage current when an appropriate reverse voltage is applied to the guard ring area. On the other hand, FGR V-SBD shows overall better electrical properties than MGR V-SBD because Al₂O₃ was widely deposited on the Ga₂O₃ surface, which prevent leakage current on the Ga₂O₃ surface.

In this study, the praseodymium-doped yttrium phosphate (YPO₄:Pr³⁺) powder, which is well known for its high luminescent efficiency, and long life in the UV range, was synthesized with various content ratios of Pr₆O₁₁ and calcination temperature. Crystal structure and luminescent properties of various phosphor powders based on different concentrations and calcination conditions were characterized by XRD (X-Ray Diffraction) and PL (photoluminescence) spectrometers. From the XRD analysis, the structure of YPO₄:Pr³⁺ which is calcinated at 1,200℃ was stable tetragonal phase and crystal size was calculated about 25 nm by Scherrer equation. PL emission of YPO4:Pr3+ with a different content ratio of Pr6O11 by excitation λexc=250 nm shows that 0.75 mol% phosphor powder has maximum PL intensity and PL decreases with the increase of the ratio of Pr₆O₁₁ up to 1.25 mol% which is caused by changes of crystallinity of phosphor powders. With increasing dopant ratio, photoluminescence Emission decreases due to Concentration quenching, which is commonly observed in phosphors. Currently, 0.75 mol% is considered the optimal doping concentration. A hybrid ultraviolet-emitting device incorporating YPO4:Pr3+ fluorescent material with plasma discharge was fabricated to enhance UV germicidal effects while minimizing ozone generation. UV emission from the plasma discharge device was shown at about 200 nm and 350 nm which caused additional emission of the regions of 250 nm, 315 nm, and 370 nm from the YPO₄:Pr³⁺ phosphor.

The Ga₂O₃ thin films were deposited using an RF sputtering system and the effect of crystallographic and optical properties under rapid thermal annealing conditions on Ga₂O₃ thin film was evaluated. A rapid thermal annealing method can fabricate a crystalline Ga₂O₃ thin film which is applied to various fields with a low cost and a high efficiency compared with the conventional post-annealing method. In this study, the Ga₂O₃ treated at 900℃ for 1 min showed the beta and gamma phases in XRD measurement. In optical properties, the crystalline Ga₂O₃ represented a high transmittance of more than 80% in the visible region and was calculated with a high optical bandgap energy of 4.58 eV. The beta and gamma phases Ga₂O₃ can be obtained by adjusting the rapid thermal annealing temperatures, and the various properties such as the optical bandgap energy can be controlled. Moreover, it is expected that crystalline Ga₂O₃ can be applied to various devices by controlling not only temperature but process time.

Recently, with the development of the smart device market, the integration of high-functional devices has increased the heat density, causing overload of the device, and resulting in various problems such as shortened lifespan, performance degradation, and failure. Therefore, research on heat dissipation materials is being actively conducted to realize next-generation electronic products. The heat dissipation material is characterized in that it is easy to dissipate heat due to its high thermal conductivity and minimizes leakage current flowing through the heat dissipation material due to its low electrical conductivity. In this study, flower-shaped Al₂O₃ and BN composites were engineered with a simple hydrothermal synthesis approach, and their thermal conductivity characteristics were compared and evaluated for each synthesis condition for the application to a heat dissipation material. Spherical BN and flower-shaped Al₂O₃ were easily obtained, and SEM/EDS analyses confirmed the uniform presence of BN between the Al₂O₃, and it can be expected that these shapes can affect the thermal conductivity.

Lithium-ion batteries are widely used in various applications, including electric vehicles and portable electronics, due to their high energy density and long cycle life. The performance of lithium-ion batteries can be improved by using solid electrolytes, in terms of higher safety, stability, and energy density. Li_1.5Al_0.5Ti_1.5(PO₄)₃ (LATP) is a promising solid electrolyte for all-solid-state lithium batteries due to its high ionic conductivity and excellent stability. However, the ionic conductivity of LATP needs to be improved for commercializing all-solid-state lithium battery systems. In this study, we investigate the microstructures and ionic conductivities of LATP by incorporating B₂O₃ glass ceramics. The smaller grain size and narrow size distribution were obtained after the introduction of B₂O₃ in LATP, which is attributed to the B₂O₃ glass on grain boundaries of LATP. Moreover, higher ionic conductivity can be obtained after B₂O₃ incorporation, where the optimal composition is 0.1 wt% B₂O₃ incorporated LATP and the ionic conductivity reaches 8.8×10^-5 S/cm, more than 3 times higher value than pristine LATP. More research could be followed for having higher ionic conductivity and density by optimizing the processing conditions. This facile approach for establishing higher ionic conductivity in LATP solid electrolytes could accelerate the commercialization of all-solid-state lithium batteries.

The effect of sputtering power on the amorphous Ga₂O₃ thin film deposited using the radio frequency sputtering system was evaluated. Amorphous Ga₂O₃ is cheaper and more efficiently fabricated than crystalline Ga₂O₃, and is studied in various fields such as RRAM, photodetector, and flexible devices. In this study, amorphous Ga₂O₃ was deposited by radio frequency sputtering system and represented a transmittance of over 80% in the visible light region and a homogeneous and dense surface. The optical band gap energy decreased as the sputtering power increased owing to the quantum size effect. Thus, the specific band gap of amorphous Ga₂O₃ can be obtained by adjusting the sputtering power, it indicates amorphous Ga₂O₃ can be used in various fields.

It was reported that a tetragonal phase can be stabilized with maintaining good piezoelectric properties when Na_0.5K_0.5NbO₃ (KNN) is modified with 0.06 mol SrTiO₃. However, such a high amount of SrTiO₃ leads not only to poor sinterability but low Curie temperature (TC). To maintain high TC with good piezoelectric properties in KNN-based lead-free piezoelectric ceramics, this study investigates the effect of Li-doping on the dielectric and piezoelectric properties of 0.96Na_0.5K_0.5NbO₃-0.04SrTiO₃ (KNN-4ST) ceramics. As a result, the orthorhombic-tetragonal phase transition was observed at 2 mol% Li₂CO₃ modified KNN-4ST ceramics, whose TC, d33 and kp values are 328℃, 165pC/N and 0.33, respectively.

In this study, the heteroepitaxial thin film growth of β-Ga₂O₃ was studied according to the position of the susceptor in mist-CVD. The position of the susceptor and substrate was moved step by step from the center of the hot zone to the inlet of mist in the range of 0~50 mm. It was confirmed that the average thickness increased to 292 nm (D1), 521 nm (D2), and 580 nm (D3) as the position of the susceptor moved away from the center of the hot zone region. The thickness of the lower region of the substrate is increased compared to the upper region. The surface roughness of the lower region of the substrate also increased because the nucleation density increased due to the increase in the lifetime of the mist droplets and the increased mist density. Therefore, thin film growth of β-Ga₂O₃ in mist-CVD is performed by appropriately adjusting the position of the susceptor (or substrate) in consideration of the mist velocity, evaporation amount, and temperature difference with the substrate, thereby determining the crystallinity of the thin film, the thickness distribution, and the thickness of the thin film. Therefore, these results can provide insights for optimizing the mist-CVD process and producing high-quality β-Ga₂O₃ thin films for various optical and electronic applications.

Gallium Oxide (Ga₂O₃) is preferred as a material for next generation power semiconductors. The Ga₂O₃ should solve the disadvantages of low thermal resistance characteristics and difficulty in forming an inversion layer through p-type ion implantation. However, Ga₂O₃ is difficult to inject p-type ions, so it is being studied in a heterojunction structure using p-type oxides, such as NiO, SnO, and Cu₂O. Research the lateral-type FET structure of NiO/Ga₂O₃ heterojunction under the Gate contact using the Sentaurus TCAD simulation. At this time, the VG-ID and VD-ID curves were identified by the thickness of the Epi-region (channel) and the doping concentration of NiO of 1 × 10¹⁷ to 1 × 10¹⁹ cm^-3. The increase in Epi region thickness has a lower threshold voltage from -4.4 V to -9.3 V at I_D = 1 × 10^-8 mA/mm, as current does not flow only when the depletion of the PN junction extends to the Epi/Sub interface. As an increase of NiO doping concentration, increases the depletion area in Ga₂O₃ region and a high electric field distribution on PN junction, and thus the breakdown voltage increases from 512 V to 636 V at I_D =1 × 10^-3 A/mm.

La_0.7-xCe_xSr_0.3MnO₃ specimens were fabricated by a solid state reaction method and structural and electrical properties with variation of Ce4+ contents were measured. All specimens exhibited a polycrystalline rhombohedral crystal structure, and the (110) peaks were shifted to low angle side with increasing the amount of Ce⁴⁺ contents. As Ce⁴⁺ ions with different ion radii and charges are substituted with La³⁺ ions, electrical properties are thought to be affected by changes in the double exchange interaction between Mn³⁺-Mn⁴⁺ ions due to distortion of the unit lattice, a decrease in oxygen vacancy concentration, and an increase in lattice defects. Resistivity gradually decrease as the amount of Ce⁴⁺ added increased, and negative temperature coefficient of resistance (NTCR) properties were shown in all specimens. In the La_0.5Ce_0.2Sr_0.3MnO₃ specimens, electrical resistivity, TCR and B-value were 31.8 Ω-cm, 0.55%/℃ and 605 K, respectively.

In this paper, we discussed the effect of field plate dielectric materials such as silicon dioxide (SiO₂), aluminum oxide (Al₂O₃), and hafnium oxide (HfO₂) on the breakdown characteristics of β-Ga₂O₃ Schottky barrier diodes (SBDs). The breakdown voltage (BV) of the SBDs with a field plate was higher than that of SBDs without a field plate. The higher dielectric constant of HfO₂ contributed to the superior reduction in electric field concentration at the Schottky junction edge from 5.4 to 2.4 MV/cm. The SBDs with HfO₂ field plate showed the highest BV of 720 V, and constant specific on-resistance (R_on,sp) of 5.6 mΩ·㎠, resulting in the highest Baliga’s figure-of-merit (BFOM) of 92.0 MW/㎠. We also investigated the effect of dielectric thickness and field plate length on BV.

La_0.7Sr_0.3-xMg_xMnO₃ (LSMMO) (x=0.05~0.20) specimens are fabricated by a solid phase sintering method, and the sintering temperature and time are 1,300℃ and 2 hours, respectively. The dependence of the crystalline structure according to the amount of Mg²⁺ contents is not observed, and all specimens show a polycrystalline rhombohedral crystal structure, the X-ray diffraction (110) peaks move to the high angle side with increasing the amount of Mg²⁺ contents. LSMMO specimens exhibit a granule-shaped microstructure with an average grain size of 1 μm or less. Resistivity gradually decrease as the amount of Mg²⁺ contents increased. And in the La_0.7Sr_0.1Mg_0.2MnO₃ specimen, resistivity and B_25/65-value are 36.7 Ω-cm and 394 K at room temperature, respectively. LSMMO specimens show a variable-range hopping (VRH) electrical conduction mechanism, and the negative temperature of coefficient of resistance (NTCR) is approximately 0.37~0.38%/℃.

In the past, the efficiency of solar cells had been increased in order to increase the efficiency of solar modules. However, in recent years, in order to increase output in the solar industry and market, the competitiveness of solar cells based on large-area solar cells and multi-bus bar has been increasing. Multi-busbar solar module is a technology to reduce power loss by increasing the number and width of the front busbar of the solar cell and reducing the current value delivered by the busbar by half through half-cutting. In the case of the existing M2 (156.75×156.75 ㎟) solar cell, even with a half-cut, power loss could be sufficiently reduced, but as the area of the solar cell is enlarged to more than M6 (166×166 ㎟), the need for more divisions emerged. This affected not only solar cells but also inverters required for module array configuration. Therefore, in this study, the electrical characteristics of a large-area solar cell and after division were extracted using Griddler simulation. The output characteristics of the module were predicted by applying the solar cell parameters after division to PSPice, and a guideline for the large-area solar module design was presented according to the number of divisions of the large-area solar cell.

Recently, as the process of the MOS device becomes more detailed, and the degree of integration thereof increases, many problems such as leakage current due to an increase in electron tunneling due to the thickness of SiO₂ used as a gate oxide have occurred. In order to overcome the limitation of SiO₂, many studies have been conducted on HfO₂ that has a thermodynamic stability with silicon during processing, has a higher dielectric constant than SiO₂, and has an appropriate band gap. In this study, HfO₂, which is attracting attention in various fields, was doped with Al and the change in properties according to its concentration was studied. Al-doped HfO₂ thin film was deposited using Plasma Enhanced Atomic Layer Deposition (PEALD), and the structural and electrical characteristics of the fabricated MIM device were evaluated. The results of this study are expected to make an essential cornerstone in the future field of next-generation semiconductor device materials.

In this paper, for the application of ultrasonic cleaners for cleaning dentures and transparent braces, Pb(Mn_1/3Nb_2/3)O₃-Pb(Ni_1/3 Nb_2/3)O₃-Pb(Zr,Ti)O₃ [PMN-PNN-PZT] system ceramics were manufactured and their dielectric and piezoelectric properties were investigated. Overall the best properties suitable for the device applications such as ultrasonic cleaner were obtained from the ceramics sintered at 920℃: bulk density of 7.8 g/㎤, the dielectric constant (ε_r) of 1,689, piezoelectric charge constant (d₃₃) of 433 pC/N, planar electromechanical coupling factor (k_p) of 0.64, mechanical quality factor (Qm) of 835, S₁₁^E of 13.37 (10^-12 N/㎡), and Curie temperature of 315℃ By using the physical properties of this composition, the ultrasonic cleaner was designed and simulated using the commercial ATILA software. For the three-layered ceramics with the dimension of 25 mm × 25 mm × 2.5mm, an excellent displacement of 8.998 ×10^-3 m) and the sound pressure of 147.68 dB were recorded.

This paper demonstrates a novel NAND flash memory structure and annealing configuration including through-silicon via (TSV) inside the silicon substrate to improve annealing efficiency using an electro-thermal annealing (ETA) technique. Compared with the conventional ETA which utilizes WL-to-WL current flow, the proposed annealing method has a higher annealing temperature as well as more uniform heat distribution, because of thermal isolation on the silicon substrate. In addition, it was found that the annealing temperature is related to the electrical and thermal conductivity of the TSV materials. As a result, it is possible to improve the reliability of NAND flash memory. All the results are discussed based on 3-dimensional (3-D) simulations with the aid of the COMSOL simulator.

YBa₂Cu₃O_7-y bulk as a high temperature oxide superconducting conductor has the high critical temperature of 92 K. YBa₂Cu₃O_7-y bulk superconductors have been fabricated by a seeded melting growth. Magnetic properties were studied by using superconductor of melted YBa₂Cu₃O_7-y oxides. It was demonstrated that Y₂BaCuO₅ particles acts as a pinning center which plays an important role on the magnetic properties. The thickness of the upper and lower pellets of the YBa₂Cu₃O_7-y bulk was formed at 40 mm with 55 g of the composition, and the YBa₂Cu₃O_7-y superconductor was manufactured through a heat treatment process. Manufacturing the superconducting bulk, it is possible to improve the pore density of the superconducting bulk by providing a path through which oxygen could be emitted.

BaTiO₃ is one of the ferroelectric materials with excellent dielectric properties such as high dielectric constant, low dielectric loss, and is widely used for the manufacturing of capacitors, piezoelectric converters, microsensors, and ferroelectric memories. Inkjet printing is a technology which uses digital and contactless methods which significantly improves flexibility associated with material and structural design, reducing manufacturing costs. Therefore, the top and bottom electrodes, BaTiO₃ ink, and photocurable resin were all printed by an inkjet to produce a BaTiO₃ capacitor. The properties of the printed thin film were analyzed. It was confirmed that the photocurable resin ink was well-infiltrated between the BaTiO₃ powder particles printed by inkjet. The dielectric properties of the capacitor such as dielectric constant which varies in accordance with frequency, polarization and tunability that changes with voltage, were measured.