This research introduces the sputtered IZO thin film transistor (TFT) with solution-processed Al₂O₃ diffusion layer. IZO is one of the most commonly used amorphous oxide semiconductor (AOS) TFT. However, most AOS TFTs have many defects that degrade performance. Especially oxygen vacancy in the active layer. In previous research, aluminum was used as a carrier suppressor by binding the oxygen vacancy and making a strong bond with oxygen atoms. In this paper, we use a solution-processed Al₂O₃ diffusion layer to fabricate stable IZO TFTs. A double-layer solution-processed Al2O3-sputtered IZO TFT showed better performance and stability, compared to normal sputtered IZO TFT.

We propose a SPICE model of drain-induced barrier lowering (DIBL) for a junctionless cylindrical surrounding gate (JLCSG) MOSFETs. To this end, the potential distribution in the channel is obtained via the Poisson equation, and the threshold voltage model is presented for the JLCSG MOSFET. In a JLCSG nano-structured MOSFET, a channel radius affects the carrier transfer as well as the channel length and oxide thickness; therefore, DIBL should be expressed as a function of channel length, channel radius, and oxide thickness. Consequently, it can be seen that DIBLs are proportional to the power of -3 for the channel length, 2 for the channel radius, 1 for the thickness of the oxide film, and the constant of proportionality is 18.5 when the SPICE parameter, the static feedback coefficient η, is between 0.2 and 1.0. In particular, as the channel radius and the oxide film thickness increase, the value of η remains nearly constant.

In our study, we collected data from a 100 kW floating photovoltaic (PV) system installed in Gyeongnam Hapcheon Dam and observed correlations between the power generation of the floating PV system and the irradiance, water temperature, humidity, ambient temperature, wind speed, and module temperature. Firstly, there was little correlation between the water temperature and power generation. Secondly, the ambient temperature, wind speed, and humidity all showed greater correlations with power generation. Finally, the power generation was very highly correlated with the irradiance and module temperature. In conclusion, the power generation of the floating PV system is related individually to environmental factors.

The shingled photovoltaic module can be produced by joining divided solar cells into a string of busbarless structure and arranging them in series and parallel to produce a module, in order to produce a high output per unit area. This paper reports a study to optimize solar cell electrode structure for shingled photovoltaic module fabrication. The characteristics of each electrode structure were analyzed according to the simulation program as follow: 80.62% fill factor in the six-junction solar cell electrode structure and 19.23% efficiency in the five-junction electrode structure. Therefore, the split electrode structure optimized for high-density and high-output shingled module fabrication is the five-junction solar cell electrode structure.

In this work, we conducted a study on cell strings of high efficiency and high power solar cell modules via simulation. In contrast to the conventional module manufacturing method, the simulation was performed by connecting cutting cells divided into four parts from 6-in size using the electrically conductive adhesive (ECA). The resistance of the ECA added in series connection was extracted using an experimental method. This resistance was found to be 3 mΩ. Based on this simulation, we verified the change in efficiency of the string as a function of the number of cutting cell connections. Consequently, the cutting cell efficiency of the first 20.08% was significantly increased to 20.63% until the fifth connection; however, for further connections, it was confirmed that the efficiency was saturated to 20.8%. Connecting cutting cells using ECA improves the efficiency of the string; therefore, it is expected that it will be possible to fabricate modules with high efficiency and high power.

The rod-shaped Ni_0.5Zn_0.5Fe₂O₄ particles were synthesized via a topotactic reaction, in which goethite (α-FeOOH) particles are the main constituents. The phases, microstructures and magnetic properties of these particles were studied using XRD, FE-SEM and VSM. The precursor solution consisted of NiSO₄·xH₂O, ZnSO₄·xH₂O, goethite and D.I. water werereacted at four different temperatures (50, 70, 90, 100℃) to generate four differently precipitated particles respectively. During the co-precipitation reaction, the pH of the solution was maintained at 8.0 using NaOH. The particles coprecipitated and calcined at a temperature of 700℃, exhibited a rod-shape similar to its original goethite, which means that the shape of Ni-Zn ferrite particles can be topotactically controlled by the goethite. The particles synthesized at 70 and 90℃ have a saturation magnetization of 29 and 35 emu/g respectively; representing better values than the ones synthesized at the 50 and 100℃, in which some second phases such as Fe₂O₃ were observed.

Liquid phases in ZnO varistors cause more complex phase development and microstructure, which makes the control of electrical properties and reliability more difficult. Therefore, we have investigated 2 mol% CaCO₃ doped ZnO-Co₃O₄-Cr₂O₃-La₂O₃ (ZCCLCa) bulk ceramics as one of the compositions without liquid phase sintering additive. The results were as follows: when CaCO₃ is added to ZCCLCa (644 Ωcm) acting as a simple ohmic resistor, CaO does not form a secondary phase with ZnO but is mostly distributed in the grain boundary and has excellent varistor characteristics (high nonlinear coefficient α＝78, low leakage current of 0.06 μA/㎠, and high insulation resistance of 1×10¹¹ Ωcm). The main defects Zn_i^·· (AS: 0.16 eV, IS & MS: 0.20 eV) and V˙_o (AS: 0.29 eV, IS & MS: 0.37 eV) were found, and the grain boundaries had 1.1 eV with electrically single grain boundary. The resistance of each defect and grain boundary decreases exponentially with increasing the measurement temperature. However, the capacitance (0.2 nF) of the grain boundary was ~1/10 lower than that of the two defects (~3.8 nF, ~2.2 nF) and showed a tendency to decrease as the measurement temperature increased. Therefore, ZCCLCa varistors have high sintering temperature of 1,200℃ due to lack of liquid phase additives, but excellent varistor characteristics are exhibited, which means ZCCLCa is a good candidate for realizing chip type or disc type commercial varistor products with excellent performance.

This study introduces a new investigation report on the microstructural and electrical property changes of ZnO-Zn₂BiVO₆-Mn₃O₄ (ZZMn), where 0.33 mol% of Mn₃O₄ and 0.5 mol% of Zn₂BiVO₆ were added to ZnO (99.17 mol%) as liquid phase sintering aids. Zn₂BiVO₆ contributes to the decrease of sintering temperatures by up to 800℃, and segregates its particles at the grain boundary, while Mn₃O₄ enhances α, the nonlinear coefficient, of varistor properties up to α＝62. In comparison, when the sintering temperature is increased from 800℃ to 1,000℃, the resistivity of ZnO grains decreases from 0.34 Ωcm to 0.16 Ωcm, and the varistor property degrades. Oxygen vacancy (V_o^·) (P1, 0.33~0.36 eV) is formed as a dominant defect. Two different kinds of grain boundary activation energies of P2 (0.51~0.70 eV) and P3 (0.70~0.93 eV) are formed according to different sintering temperatures, which are tentatively attributed to be ZnO/Zn₂BiVO₆-rich interface and ZnO/ZnO interface, respectively. Accordingly, this study introduces a progressive method of manufacturing ZnO chip varistors by way of sintering ZZMn-based varistor under 900℃. However, to procure a higher reliability, an in-depth study on the multi-component varistors with double-layer grain boundaries should be executed.

SiGe thin films were deposited by remote plasma enhanced chemical vapor deposition (RPE-CVD) at 400℃ using SiH₄ or SiCl₄ and GeCl₄ as the source of Si and Ge, respectively. The growth rate and the degree of crystallinity of the fabricated films were characterized by scanning electron microscopy and Raman analysis, respectively. The optical and electrical properties of SiGe films fabricated using SiCl₄ and SiH₄ source were comparatively studied. SiGe films deposited using SiCl₄ source showed a lower growth rate and higher crystallinity than those deposited using SiH4 source. Ultraviolet and visible spectroscopy measurement showed that the optical band gap of SiGe is in the range of 0.88~1.22 eV.

Red phosphor in glasses (PiGs) for automotive light-emitting diode (LED) applications were fabricated with 620-nm CaAlSiN₃:Eu²⁺ phosphor and Pb-free silicate glass. PiGs were synthesized and mounted on high-power blue LED to make a monochromatic red LED. PiGs were simple mixtures of red phosphor and transparent glass powder. After being fabricated with uniaxial press and CIP at 300 MPa for 20 min, the green bodies were thermally treated at 550℃ for 30 min to produce high dense PiGs. As the phosphor content increased, the density of the sintered body decreased and PiGs containing 30% phosphor had a full sintered density. Changes in photoluminescence spectra and color coordination were studied by varying the thickness of plates that were mounted after optical polishing. As a result of the optical spectrum and color coordinates, PiG plate with 210 μm thickness showed a color purity of 99.7%. In order to evaluate the thermal stability, the thermal quenching characteristics were measured at temperatures of 30~150℃. The results showed that the red PIG plates were 30% more thermally stable compared to the AlGaInP red chip.

With the development of the Internet of Things, the use of flexible displays has become widespread. In particular, the use of curved, bendable, and rollable displays is increasing. Flexible display production processes include various important components such as lamination material, flexible substrates, and adhesives. Among them, improvement of the lamination process comprises a large proportion of efforts for further development. In this paper, we attempt to improve the transmittance of the display substrate by performing a bubble removal process after adhesion. The transmittance of the glass substrate with the bubble removal process was 5~12% higher than that of the substrate without the bubble removal process. The fill-strength after the bubble removal process was improved by 21.4%, and the shear-strength was improved by 43.9%.

Transition metal oxide materials have attracted widespread attention as Li-ion battery electrode materials owing to their high theoretical capacity and good Li storage capability, in addition to various nanostructured materials. Here, we fabricated a CoO Li-ion battery in which Co nanoparticles (NPs) are deposited into a current collector through electrophoretic deposition (EPD) without binding and conductive agents, enabling us to focus on the intrinsic electrochemical properties of CoO during the conversion reaction. Through optimized Co NP synthesis and electrophoretic deposition (EPD), CoO Li-ion battery with 630 mAh/g was fabricated with high cycle stability, which can potentially be used as a test platform for a fundamental understanding of conversion reaction.

In order to achieve a high efficiency for the silicon solar cell, a passivation characteristic that minimizes the electrical loss at a silicon interface is required. In this paper, we evaluated the applicability of the oxide film formed by ozone for the tunnel silicon oxide film. To this end, we fabricated the silicon oxide film by changing the condition of ozone oxidation and compared the characteristics with the oxide film formed by the existing nitric acid solution. The ozone oxidation was formed in the temperature range of 300~500℃ at an ozone concentration of 17.5 wt%, and the passivation characteristics were compared. Compared to the silicon oxide film formed by nitric acid oxidation, implied open circuit voltage (iVoc) was improved by ~20 mV in the ozone oxidation and the ozone oxidation after the nitric acid pretreatment was improved by ~30 mV.

Nanomaterials have considerable potential to solve several key challenges in various electrochemical devices, such as fuel cells. However, the use of nanoparticles in high-temperature devices like solid-oxide fuel cells (SOFCs) is considered problematic because the nanostructured surface typically prepared by deposition techniques may easily coarsen and thus deactivate, especially when used in high-temperature redox conditions. Herein we report the synthesis of a self-regenerated Pd metal nanoparticle on the perovskite oxide anode surface for SOFCs that exhibit self-recovery from their degradation in redox cycle and CH₄ fuel running. Using Pd-doped perovskite, La(Sr)Fe(Mn, Pd)O₃, as an anode, fairly high maximum power densities of 0.5 and 0.2 cm^-2 were achieved at 1,073 K in H₂ and CH₄ respectively, despite using thick electrolyte support-type cell. Long-term stability was also examined in CH₄ and the redox cycle, when the anode is exposed to air. The cell with Pd-doped perovskite anode had high tolerance against re-oxidation and recovered the behavior of anodic performance from catalytic degradation. This recovery of power density can be explained by the surface segregation of Pd nanoparticles, which are self-recovered via re-oxidation and reduction. In addition, self-recovery of the anode by oxidation treatment was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Commonly, a live-line alarm can be used to measure the electric field strength of a high-voltage system to calculate its current, but it is hard to detect the electric field of shielded cables or concealed structures, such as underground distribution cables. Current sensors can detect the magnetic field in a single core wire, but they cannot determine the magnetic field about a double-core wire because the currents flow in opposite directions. Therefore, it is very difficult to detect certain current problems, such as a fault current in an extension line comprised of a double line. In this paper, to ultimately develop a sensor that can detect the current regardless of line conditions, we used a simulation to determine the concentration of the magnetic field dependent on the distribution of the external magnetic field and the path of each line’s core.