Lead-free bismuth sodium titanate (BNT)-based ceramics have attracted strong attention as environmentally benign dielectric materials for high-efficiency electrostatic energy-storage capacitors. A key challenge is that pristine BNT typically exhibits large hysteresis, high remnant polarization, and limited dielectric reliability, which restrict recoverable energy storage and efficiency under practical electric fields. Here, we present a focused mini-review of recent studies to clarify how composition design, phase boundary tuning, defect chemistry, and microstructural control collectively enable slim or pinched polarization-electric field (P-E) behavior and improved energy-storage functionality in BNT-related bulk ceramics. The reviewed outcomes consistently show that stabilizing relaxor states governed by polar nanoregions (PNRs), often via solid-solution engineering and secondary relaxor/antiferroelectric-like incorporation, suppresses irreversible switching and reduces hysteresis loss, while densification and grain-size control enhance electrical homogeneity and breakdown strength. In addition, defect-mediated tuning of oxygen vacancy-related complexes is highlighted as an independent lever to control relaxor ergodicity and polarization reversibility, providing a complementary route to slim-loop optimization. These insights are expected to guide integrated design strategies that couple phase/relaxor-state engineering with defect and microstructure optimization, accelerating the development of reliable, temperature-robust, lead-free dielectric capacitors based on BNT-related ceramics.

The recent rapid adoption of electric vehicles (EVs) is creating new load characteristics in the distribution system, and in particular, the widespread use of single-phase charging methods is exacerbating phase load imbalances, leading to voltage unbalance issues. Such voltage imbalances can undermine the stability of the distribution system and may cause side effects such as reduced power quality and shortened equipment lifespan. This study proposes a smart distribution panel system that can detect voltage imbalance issues caused by uneven electric vehicle charging loads in real time and actively compensate for them. The proposed system aims to contribute to the stability and power quality improvement of the distribution network by integrating a load balancing algorithm with inter-phase voltage monitoring functionality.

The increasing global demand for renewable energy has accelerated the deployment of offshore wind farms, thereby highlighting the need for advanced development and performance assessment techniques for dynamic submarine cables used in floating offshore wind systems. These cables are continuously subjected to combined thermal, electrical, and mechanical stresses, with mechanical loading playing a particularly dominant role. As a result, dynamic submarine cables exhibit degradation behaviors that differ significantly from those of conventional fixed submarine cables. This paper presents the design and implementation of a comprehensive evaluation system capable of applying combined thermal, electrical, and mechanical stresses to dynamic submarine cables. The system was validated using a 66 kV wet type submarine cable through commissioning tests and insulation performance measurements. Electrical stress of 72 kV, thermal stress exceeding 95°C, and mechanical stress corresponding to a bending radius of 20 times the cable diameter over 20 cycles were applied to verify system reliability. The subsequent insulation assessments quantitatively confirmed performance variations induced by the combined stresses. The results demonstrate that the proposed platform is the first system capable of simultaneously applying thermal, electrical, and mechanical stresses to dynamic submarine cables, and its operational performance has been successfully validated. This platform enables realistic reliability evaluation of dynamic cables used in floating offshore wind farms and is expected to improve the overall operational reliability of offshore wind power systems.

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.

AlGaN/GaN High Electron Mobility Transistors (HEMTs) are emerging as next-generation semiconductors optimized for high-power and high-frequency applications, with their performance highly dependent on the surface and interface quality of the AlGaN/GaN structure. In particular, the 2-Dimensional Electron Gas (2DEG) formed in the AlGaN layer is susceptible to trapping by surface defects, which degrades electrical characteristics and makes the device vulnerable to degradation. In this study, we propose an approach to enhance device reliability and performance by forming a gallium oxynitride (GaON) interfacial layer through O₂ plasma treatment on the AlGaN surface. This method effectively suppresses interface defects, resulting in improved electrical properties such as reduced interface trap density (Dit), threshold voltage (Vth) shift, increased drain current density (Id), and enhanced transconductance density (gm). Furthermore, this surface treatment demonstrates the potential for process simplification by improving the electrical characteristics of power semiconductor devices without the need for complex deposition steps.

To ensure the long-term reliability of flexible photovoltaic (FPV) modules, it is crucial to develop an effective moisture barrier layer that prevents the infiltration of moisture and oxygen. We developed such a layer composed of parylene (700 nm) and AlOx (70 nm), optimizing its material properties, moisture-blocking performance, and processing conditions. The barrier layer applied to the Ethylene Tetrafluoroethylene (ETFE) substrate demonstrated a water vapor transmission rate (WVTR) of 6.33 × 10^-2 g/m²/day and an average visible light transmittance (AVT) of 85.3% over the 380-780 nm wavelength range. For the FPV module with this barrier, Damp/Heat (DH) reliability testing was conducted at 85℃ and 85% relative humidity for up to 1,000 hours. During testing, the power conversion efficiency (PCE) decreased slightly from 25.4% (0 hr) to 24.7% (1,000 hr), reflecting a minimal reduction of only 0.7%. The primary cause of degradation was identified as a -4% relative change in shortcircuit current density (JSC) before and after DH testing. Consequently, the ETFE/parylene/AlOx multilayer moisture barrier proved highly effective in ensuring the long-term reliability of solar modules.

Cathodoluminescence (CL) spectroscopy provides valuable insights into the optical and electronic properties of materials by analyzing photon emission induced by electron beam excitation. In this study, we present a novel CL detection system integrated into a transmission electron microscope (TEM) specimen stage, enabling high-resolution optical analysis of internal microstructures. The system features a parabolic mirror, a focusing lens, and a UV-VIS range optical fiber to maximize light collection and transmission efficiency, with performance further enhanced by a liquid nitrogen cooling setup. Using this system, we successfully performed CL mapping of InGaN/GaN multiple quantum wells (MQWs) and GaN thin films. The results revealed that threading dislocations act as non-radiative centers in GaN and locally increase the bandgap energy in InGaN MQWs, causing a blue-shift in CL emission. These findings support a model in which dislocations induce carrier delocalization, preserving high radiative efficiency despite high dislocation densities. This work demonstrates the effectiveness of the TEM-integrated CL system for nanoscale optical characterization, offering a new pathway for studying defect-related phenomena in semiconductor materials.

Molybdenum disulfide (MoS₂) is a promising 2D semiconductor material for low-power electronics due to its excellent electrical properties and compatibility with conventional processes. In this study, MoS₂ thin films deposited by RF sputtering were etched using Cl₂/Ar plasma in an ICP system. The effects of Cl₂ gas ratio, RF power, and process pressure on etch rate and MoS₂/SiO₂ selectivity were investigated. Optimal results were obtained at 25% Cl₂, achieving ~38 nm/min etch rate and selectivity of 3.0. Increased source power improved both etch rate and selectivity, while higher bias power enhanced etching but reduced selectivity due to stronger ion bombardment. XPS analysis confirmed Mo－Cl and S－Cl bond formation after etching, indicating chemical reactions and some by-product residue. These results provide insights into optimized plasma etching of sputtered MoS₂ films for advanced 2D device fabrication

The mounting demand for sustainable, self-powered biomedical devices, particularly those engineered for extreme environments, has established triboelectric nanogenerators (TENGs) as a prominent technology in energy harvesting research. This review examines state-of-the-art biomaterial synthesis strategies essential for developing high-performance bioelectronic TENGs that can operate reliably under harsh conditions, including elevated temperatures, extreme humidity, and mechanical strain. It begins with a comprehensive overview of the fundamental principles of triboelectricity and subsequently addresses the pivotal challenges associated with efficient charge generation and retention in such challenging settings. The content places particular emphasis on recent advancements in composite material engineering and structure design for high-efficiency mechanisms, with a particular focus on biocompatible and environmentally resilient materials. The integration of TENGs into wearable sensors, implantable devices, and self-powered monitoring systems is also investigated, demonstrating their transformative potential for bioelectronic applications. Our goal subsequently underscores persistent limitations to overcome, including those pertaining to fabrication scalability and long-term operational stability, while concurrently proposing prospective research directions. Consequently, this work underscores how innovative biomaterial synthesis and bioelectronic devices can enable the development of next-generation, high-performance, self-powered devices suited for extreme biomedical environments.

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%.

SMD-type 660 nm wavelength semiconductor laser diode device is fabricated using silicon resin molding technology and fabricated a BT resin printed circuit board. BT resin electrode structure printed circuit boards with soldering electrode pads and through holes for heat dissipation were fabricated. The SMD process is an injection molding technique in which the chip is molded from silicon material and then cut by a dicing process to complete the beam emission surface. The fabricated SMD-type semiconductor laser diode exhibits a good near-field beam pattern with no scattering/dispersion caused by the printed circuit board or silicon molding in the emitted laser beam, or reflections around the chip. It was also confirmed that the heat generated at 20 mA operation has good heat dissipation characteristics through the through-hole heat dissipation structure.

Recently, oxide semiconductors have assumed a pivotal role in electronic displays and transparent electronic devices such as amorphous indium gallium zinc oxide (a-IGZO), characterized by high electron mobility and excellent stability. a- IGZO is very suitable for next-generation applications such as flexible displays because it is possible to manufacture highperformance transistors even at low temperatures. However, since the electrical properties tend to deteriorate in hightemperature environments, research aimed at improving thermal stability is needed. In this study, a low-temperature plasma annealing process was introduced to improve the high-temperature stability of the a-IGZO thin film. This process enhances electron mobility by reducing defects in the a-IGZO film and provides stable device performance even under high-temperature conditions. As a result of the experiments of 5 min, 10 min, 15 min, and 20 min, the a-IGZO TFT, which was subjected to plasma annealing at 160℃ for 5 min, showed the best electrical performance, especially in charge mobility and current-voltage characteristics. The technical potential for improving the performance of a-IGZO-based display device was emphasized, and the foundation for applying this power generation to flexible displays and next-generation electronic devices was laid. Future research will focus on determining the optimal annealing conditions by exploring various temperature ranges and plasma parameters to integrate these results into the actual device manufacturing process. These efforts are expected advance significantly to advancing next-generation high-performance display technology.

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.

The display industry has recently been at the forefront of innovative advancements in modern electronic devices. Technological progress such as flexible display holds significant potential across various application fields, particularly in wearable devices and rollable displays. A low-temperature process is essential for fabricating such displays. One of the key technologies in displays is the thin film transistor (TFT), with amorphous indium gallium zinc oxide (a-IGZO) receiving particular attention. a-IGZO is widely applied in high-performance displays due to its high charge mobility and stability. While a thermal treatment above 350℃ is typically required to maximize the electrical performance of a-IGZO TFTs, such high temperatures pose challenges for utilizing polymer substrates like plastics. Here, we thesis investigates the simultaneous lowtemperature plasma annealing process to develop next-generation high-performance flexible display devices. To define the optimal temperature, devices were fabricated and analyzed at varying temperatures of 40℃, 80℃, 120℃, and 160℃. Experimental results indicated that devices fabricated at 160℃ and 80℃ exhibited superior performance, with those at 160℃ demonstrating better performance in terms of current ratio, threshold voltage, and subthreshold swing. These findings confirm that the simultaneous low-temperature plasma annealing process is effective for next-generation high-performance displays.

The possibility of a dye-sensitized solar cell (DSSC) submodule was evaluated as an independent power source that can drive a smart liquid crystal window (SLW) that selectively blocks sunlight when electricity is applied. In order to save energy and increase the functionality of buildings, SLW operation was supplied directly from DSSC submodule, rather than connecting to the existing power system and external power sources. It was confirmed that the SLW can control light transmittance through self-generation using the DSSC submodule composed of 6 cells at low light of 2,500 lux. These results imply that there is a high possibility of combining smart windows and DSSCs suitable for window-type building-integrated photovoltaic (BIPV) systems. DSSCs, which can self-generate power in low light, are expected to increase their usability in urban BIPV systems through combination with smart window technology.

Precise control over the morphology of nanostructures is critical for tailoring their physical and chemical properties. This study addresses the challenge of developing a simple, integrated method for synthesizing both 1D and 2D colloidal Cu nanostructures in a single system, achieving successful tuning of their localized surface plasmon resonance (LSPR) properties. A facile hydrothermal synthesis utilizing potassium iodide (KI) and hexadecylamine (HDA) is presented for controlling Cu nanostructure morphologies. The key to achieving 1D nanowires (NWs) and 2D nanoplates (NPs) depends on the controlled adsorption of HDA molecules and iodide (I-) ions on specific crystal facets. Depending on the morphologies, the resultant Cu nanostructures exhibit tunable LSPR peaks from 558 nm [nanoplates (NPs)] to 590 nm [nanowires (NWs)]. These results pave the way for the scalable and cost-effective production of plasmonic Cu nanostructures with tunable optical properties, holding promise for applications in sensing, catalysis, and photonic devices.

Oxygen evolution reaction is a critical bottleneck for the development of efficient electrochemical hydrogen production because of its sluggish reaction. Among various catalysts, transition metal-based layered double hydroxide has drawn significant attention due to their excellent catalytic properties and cost-effectiveness. This paper begins with basic crystal structures, and then conventional adsorbate evolution mechanism of layered double hydroxide. Strategies for enhancing catalytic properties based on adsorbate evolution mechanism and lattice oxygen mechanism that could surpass theoretical limit of adsorbate evolution mechanism are discussed. This paper ends with a brief discussion on the challenges and future directions of layered double hydroxide-based oxygen evolution reaction catalysts.

This research explores the development of [100]-textured barium titanate (BaTiO₃, BT) ceramics using sodium bismuth titanate (Na_0.5Bi_4.5Ti₄O₁₅, NBiT) templates, aimed at leveraging the inherent high dielectric property of BT. However, the attempted texturing was unsuccessful, primarily due to bismuth diffusion from the NBiT templates into the BT matrix below the sintering temperature, at 1,000℃. Systematical exploration about the cause of the failure is involved and alternative approaches are proposed in detail to overcome the challenge. These findings contribute to the understanding of techniques and conditions for textured ceramic fabrication and highlight the need for further research in this area.

Laser-induced plasmonic sintering of metal nanoparticles (NPs) holds significant promise as a technology for producing flexible conducting electrodes. This method offers immediate, straightforward, and scalable manufacturing approaches, eliminating the need for expensive facilities and intricate processes. Nevertheless, the metal NPs come at a high cost due to the intricate synthesis procedures required to ensure long-term reliability in terms of chemical stability and the prevention of NP aggregation. Herein, we induced the self-generation of metal nanoparticles from Ag organometallic ink, and fabricated highly conductive electrodes on flexible substrates through laser-assisted plasmonic annealing. To demonstrate the practicality of the fabricated flexible electrode, it was configured in a mesh pattern, realizing multi-touchable flexible touch screen panel.

This paper introduces an optimized oxygen (O₂) plasma surface treatment technique to enhance sphere lithography on hydrophobic photoresist surfaces. The focus is on semiconductor manufacturing, particularly the creation of finer structures beyond the capabilities of traditional photolithography. The key breakthrough is a method that makes substrate surfaces hydrophilic without altering photoresist patterns. This is achieved by meticulously controlling the O₂ plasma treatment duration. The result is the consistent formation of nano and microscale patterns across large areas. From an academic perspective, the study deepens our understanding of surface treatments in pattern formation. Industrially, it heralds significant progress in semiconductor and precision manufacturing sectors, promising enhanced capabilities and efficiency.

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 effects of the annealing temperature on the structural, morphological, and luminescent properties of SrWO₄:Sm³⁺ thin films grown on quartz substrates by radio-frequency magnetron sputtering were investigated. The thin films were annealed at various annealing temperatures for 20 min in a rapid thermal annealer after growing the thin films. The experimental results showed that the annealing temperature has a significant effect on the properties of the SrWO₄:Sm³⁺ thin films. The crystal structure of the as-grown SrWO₄:Sm³⁺ thin films was transformed from amorphous to crystalline after annealing at 800℃. The preferred orientation along (112) plane and a significant increase in average grain size by 820 nm were observed with increasing the annealing temperature. The average optical transmittance in the wavelength range of 500~1,100 nm was decreased from 72.0% at 800℃ to 44.2% at an annealing temperature of 1,000℃, where the highest value in the photoluminescence intensity was obtained. In addition to the red-shift of absorption edge, a higher annealing temperature caused the optical band gap energy of the SrWO₄:Sm³⁺ thin films to fall rapidly. These results suggest that the structural, morphological, and luminescent properties of SrWO4:Sm3+ thin films can be controlled by varying annealing temperature.

Flash lamp annealing (FLA) of metal nanoparticle (NP) ink has provided powerful strategies to fabricate highperformance electrodes on a flexible substrate because of its rapid processing capability (in milliseconds), low-temperature process, and compatibility with to roll-to-roll process. However, metal NPs [e.g., gold (Au), silver (Ag), copper (Cu), etc.] have limitations such as difficulty in synthesizing fine metal NPs (diameter less than 10 nm), high price, and degradation during ink storage and FLA processing. In this regard, organometallic ink has been proposed as a material that can replace metal NPs due to their low-cost (usually 1/100 times cheaper than metal nano inks), low-temperature processability, and high material stability. Despite these advantages, the fabrication of flexible electrodes through FLA treatment of organometallic compounds has not been extensively researched. In this paper, we experimentally guide how to determine the optimal conditions for forming electrodes on flexible substrates by considering material parameters, and flashlight processing parameters (energy density, pulse duration, etc) to minimize the difficulties that may arise during the FLA of organometallic ink.

The utilization of scanning transmission electron microscopy (STEM) in conjunction with cathodoluminescence (CL) has emerged as a valuable tool for the investigation of material optical properties. In recent years, this technique has facilitated significant advancements in the fields of plasmonics and quantum emitters by surpassing prior technical restrictions. The review commences by providing an outline of the diverse STEM-CL operating modes and technical aspects of the instrumentation. The review explains the fundamental physics of light production under electron beam irradiation and the physical basis for interpreting STEM-CL experiments for different types of excitations. Additionally, the review compares STEM-CL to other related techniques such as scanning electron microscope CL, photoluminescence, and electron energy-loss spectroscopy.

The characteristics of write discharge were investigated when the conventional driving method with the unipolar sustain voltages, and the single sustain driving method applying the bipolar sustain voltage were applied in an AC plasma display. In the case of having a single sustain waveform, the strength of the write discharge is weakened compared to the conventional driving method during the address period, because the wall charge inside the panel is more dissipated by the lower scanning voltage. In the driving method with a single sustain waveform, the bias voltage of the other electrodes was changed to improve the write discharge characteristics. As a result, the intensity of the discharge was enhanced by 32% and the delay time was shortened by 60 μs.

Novel self-illuminated smart windows were fabricated consisting of Cu-doped ZnS (ZnS:Cu) powder and polymer-dispersed liquid crystal (PDLC). This smart window shows not only switchable transparency but also self-illumination without any attachable luminous body. Its electro-optical characteristics, transmittance, and luminance were investigated in relation to various applied voltages and composition ratios. The optical transmittance and luminous intensity increased with increasing applied voltages. However, the optical transmittance decreased with increasing ZnS:Cu powder content. One of the self-illuminated smart windows, which was fabricated with 9 wt% of ZnS:Cu, achieved the optical transmittance of 60.5% (at 550 nm) and the luminance of 11.0 cd/m² at 100 V. This smart window could be used as a normal switchable smart window in daytime and light-emitting signage at night.

Laser-induced plasmonic sintering of metal nanoparticles (NPs) is a promising technology to fabricate flexible conducting electrodes, since it provides instantaneous, simple, and scalable manufacturing strategies without requiring costly facilities and complex processes. However, the metal NPs are quite expensive because complicated synthesis procedures are needed to achieve long-term reliability with regard to chemical deterioration and NP aggregation. Herein, we report laser-induced Ag NP self-generation and sequential sintering process based on low-cost Ag organometallic material for demonstrating highquality microelectrodes. Upon the irradiation of laser with 532 nm wavelength, pre-baked Ag organometallic film coated on a transparent polyimide substrate was transformed into a high-performance Ag conductor (resistivity of 2.2 × 10^-4 Ω·cm). To verify the practical usefulness of the technology, we successfully demonstrated a wearable transparent heater by using Ag-mesh transparent electrodes, which exhibited a high transmittance of 80% and low sheet resistance of 7 Ω/square.

As the 4th industrial revolution based on ICT is progressing in the manufacturing field, interest in building smart factories that can be flexible and customized according to customer demand is increasing. To this end, it is necessary to maximize the efficiency of factory by performing an automated process in real time through a network communication between engineers and equipment to be able to link the established IT system. It is also necessary to collect and store real-time data from heterogeneous facilities and to analyze and visualize a vast amount of data to utilize necessary information. Therefore, in this study, four types of controllers such as PLC, Arduino, Raspberry Pi, and embedded system, which are generally used to build a smart factory that can connect technologies such as artificial intelligence (AI), Internet of Things (IoT), and big data, are configured. This study was conducted for the development of a program that can collect and store data in real time to visualize and manage information. For communication verification by controller, data communication was implemented and verified with the data log in the program, and 3D monitoring was implemented and verified to check the process status such as planned quantity for each controller, actual quantity, production progress, operation rate, and defect rate.

Resistive switching behaviors of a co-sputtered zinc silicate thin film (ZnO and SiO₂ targets) have been investigated. We fabricated an Ag/ZnSiO_x/highly doped n-type Si substrate device by using an RF magnetron sputter system. X-ray diffraction pattern (XRD) indicated that the Zn₂SiO₄ was formed by a post annealing process. A unique morphology was observed by scanning electron microscope (SEM) and atomic force microscope (AFM). As a result of annealing process, 50 nm sized nano clusters were formed spontaneously in 200~300 nm sized grains. The device showed a unipolar resistive switching process. The average value of the ratio of the resistance change between the high resistance state (HRS) and the low resistance state (LRS) was about 106 when the readout voltage (0.5 V) was achieved. Resistance ratio is not degraded during 50 switching cycles. The conduction mechanisms were explained by using Ohmic conduction for the LRS and Schottky emission for the HRS.

We present the structural and optical properties of Au@TiO₂ core-shell microsphere structure prepared by a hydrothermal synthesis method. As a way to improve the efficiency of organic solar cells, the Au@TiO₂ core-shell microsphere was synthesized to use the local surface plasmon resonance (LSPR) phenomenon. The synthesized results were confirmed to have the Au@TiO₂ core-shell structure using a high-resolution transmission electron microscopy. An absorption was observed to occur at 527 nm belonging to the visible light region using a visible light spectroscopy, which supports the LSPR phenomenon. We suggest that the Au@TiO₂ core-shell microsphere is highly likely to be applied to organic solar cells including dye-sensitized solar cells. In addition, we expect it to be widely used not only in the energy but also in the bio as well as in the environmental fields.