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We report the cause of degradation of low-temperature amorphous indium-gallium-zinc-oxide (a-IGZO) coplanar thin-film transistors (TFTs). As the deposition temperature of the buffer layer was changed from 400 to 200 °C, the field-effect mobility decreased considerably from 15 to 3 cm2 V−1 s−1, the subthreshold swing (SS) increased from ~ 150 to 280 mV dec−1, the threshold voltage shift (ΔVth) under negative bias temperature stress (NBTS) increased from − 0.27 to − 0.33 V, and ΔVth under a positive bias temperature stress (PBTS) increased significantly from 0 to 4.9 V. From the results of high-resolution transmission electron microscopy (HR-TEM) and X-ray reflectivity (XRR), the poor roughness created by sputtering damage of the interface between the gate insulator (GI) and the a-IGZO is the cause of degradation. In addition, through an atomic probe tomography (APT) analysis, the reason low-temperature TFTs have poorer PBTS stability than NBTS is carefully to be due to zinc (Zn)-related defects that create ionized oxygen vacancies. Based on these results, we introduce strategies for realizing low-temperature oxide TFTs using vacuum process. Please confirm if the author names are presented accurately and in the correct sequence as given name, middle name/initial, family name. Also, kindly confirm the details in the metadata are correct. We confirmed all author names. Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary. We checked all authors and their affiliations.

An ion accelerator, RAON, is going to be built in Daejeon, Korea, by the Rare Isotope Science Project (RISP) team in the Institute of Basic Science (IBS). In this accelerator, various ions, such as uranium, proton, carbon and calcium, will be accelerated and fed to researchers for experiments. To produce the ion beams and to satisfy the requirements, many devices such as accelerating structures, RF power supplies and ion sources will be installed and controlled according to the predefined control logic. For correct control of such devices, time and clock synchronization is essential. A time synchronization test bed is planned for the RAON superconducting radio-frequency (SRF) test facility, and a flexible, low-cost gps-based time server was developed for that purpose. In this paper, detailed information on the developed GPS server and the test results will be described.

This study was performed to characterize pear protease proteolytic activity and investigate the use of pear protease as a meat tenderizer. Pear protease was purified and stabilized by 5% dextrin during lyophilization (dry) or concentration (liquid). Pear protease was further characterized with respect to pH, thermodynamics, and enzyme kinetics. Pear protease was stable at a pH range of 5-8 with an optimum pH of 6.5. From Arrhenius plots, liquid protease showed higher temperature dependency (23.49 kJ/mol) than dry protease (18.62 kJ/mol) due to its higher activation energy. The kcat/Km, catalytic efficiency of enzyme, was similar with 2.9 and 2.7 µM/min with dry and liquid proteases. Pear protease was evaluated for its proteolytic activities with casein and beef myofibrillar proteins by individually and combination with fig and kiwifruit proteases. These result indicated that pear and kiwifruit proteases could be complementary to be a desirable product for meat tenderization.

We report the performance improvement of low-temperature coplanar indium&ndash, gallium&ndash, zinc&ndash, oxide (IGZO) thin-film transistors (TFTs) with a maximum process temperature of 230 &deg, C. We treated F plasma on the surface of an SiO2 buffer layer before depositing the IGZO semiconductor by reactive sputtering. The field-effect mobility increases from 3.8 to 9.0 cm2 V&minus, 1&middot, s&minus, 1, and the threshold voltage shift (&Delta, Vth) under positive-bias temperature stress decreases from 3.2 to 0.2 V by F-plasma exposure. High-resolution transmission electron microscopy and atom probe tomography analysis reveal that indium fluoride (In-F) nanoparticles are formed at the IGZO/buffer layer interface. This increases the density of the IGZO and improves the TFT performance as well as its bias stability. The results can be applied to the manufacturing of low-temperature coplanar oxide TFTs for oxide electronics, including information displays.

As the share of agriculture in Korean economy has been decreasing since the 1970s, the Korean agricultural workforce has also declined and agricultural workers in their twenties and thirties have become scarce. Recent Korean agricultural labor productivity is stagnant in growth. Since the 1980s, Korea has been trying to secure young generation in the agriculture sector and rural areas by launching new programs such as Farm Successor Fostering Program (1981), Korea National Agricultural College (1997), and Special Agricultural Program in Agricultural Schools (2006). While each program has its own outcomes, the greying of Korean farmers is likely to continue because of less favorable public perceptions of agriculture, farm youth decrease, old farm retirement and entry, and agricultural school graduates’ scarce entry into farming. In order to solve these problems, this study suggested the following measures: activating education about agriculture; fostering selected agricultural high schools; strengthening the role of agricultural colleges in fostering agricultural workforce; linking retiring farmers and new farmers through farm corporations; launching intermediate organizations in charge of regional agricultural workforce; and supporting capital formation of young farmers.

We propose new mask reduction process for high resolution TFT-LCD using organic dielectrics (eg. PAC). After the Vcom layer is patterned, we use the Vcom layer as a mask for etching the organic layer underneath. Finally, we reduced mask processes so that AH-IPS display with organic dielectrics could be made by 5 mask process.

A non-classical organic strain gauge as a voltage signal sensor is reported, using an inverter-type thin-film transistor (TFT) circuit, which is able to sensitively measure a large quantity of elastic strain (up to ≈2.48%), which approaches an almost folding state. Novel heptazole-based organic TFTs are chosen to be incorporated in this gauge circuit; organic solid heptazole has small domain size in general. While large crystal domain-pentacene TFTs seldom show sufficient current variation upon mechanical bending for tensile strain, these heptazole TFTs demonstrate a significant variation for the same strain condition as applied to pentacene devices. In addition, the pentacene channel does not recover to its original electric state after bending but heptazole channels are very elastic and reversible, even after going through serious bending. More interesting is that the heptazole TFTs show only a little variation of signal current under horizontal direction strain, while they make a significant amount of current decrease under vertical direction strain. Utilizing the anisotropic response to the tensile bending strain, an ultrasensitive voltage output strain gauge composed of a horizontally and vertically oriented TFT couple is demonstrated.

DNA-base small molecules of guanine, cytosine, adenine, and thymine construct the DNA double helix structure with hydrogen bonding, and they possess such a variety of intrinsic benefits as natural plentitude, biodegradability, biofunctionality, low cost, and low toxicity. On the basis of these advantages, here, we report on unprecedented useful applications of guanine layer as hydrogen getter and charge trapping layer when it is embedded into a dielectric oxide of n-channel inorganic InGaZnO and p-channel organic heptazole field effect transistors (FETs). The embedded guanine layer much improved the gate stability of inorganic FETs gettering many hydrogen atoms in the gate dielectric layer of FET, and it also played as charge trapping layer to which the voltage pulse-driven charges might be injected from channel, resulting in a threshold voltage (Vth) shift of FETs. Such shift state is very ambient-stable and almost irrevocable even under a high electric-field at room temperature. So, Boolean logics are nicely demonstrated by using our FETs with the guanine-embedded dielectric. The original Vth is recovered only under high energy blue photons by opposite voltage pulse (charge-ejection), which indicates that our device is also applicable to nonvolatile photo memory.

In order to realize a high resolution and high throughput printing method for thin film transistor application, a modified offset roll printing was studied. This roll printing chiefly consists of a blanket with low surface energy and a printing plate (cliche) with high surface energy. In this study, a finite element analysis was done to predict the blanket deformation and to find the optimal angle of cliche's sidewall. Various etching methods were investigated to obtain a high resolution cliche and the surface energy of the blanket and cliche was analyzed for ink transfer. A high resolution cliche with the sidewall angle of 90^o and the intaglio depth of [email protected] was fabricated by the deep reactive ion etching method. Based on the surface energy analysis, we extracted the most favorable condition to transfer inks from a blanket to a cliche, and thus thin films were deposited on a Si-cliche to increase the surface energy. Through controlling roll speed and pressure, two inks, etch-resist and silver paste, were printed on a rigid substrate, and the fine patterns of [email protected] width and [email protected] line spacing were achieved. By using this printing process, the top gate amorphous indium-gallium-zinc-oxide TFTs with channel width/length of 12/[email protected] were successfully fabricated by printing etch-resists.

A new technology for reducing photolithography process from a four step to a three step process in the fabrication of TFT LCD is introduced. The core technology for 3‐mask‐TFT processes is the lift‐off process [1], by which the PAS and PXL layers can be formed simultaneously. A different method of the lift‐off process was developed in order to enhance the performance of efficiency with conventional positive and not negative PR which is the generally used in other lift‐off process. In addition, the removal capacity of the ITO/PR in lift‐off process was evaluated. The evaluation results showed that the new process can be run in conventional TFT production condition. In order to apply this new process in existing TFT process, several tests were conducted to ensure stability of the TFT process. It was found that the outgases from PR on the substrate in ITO sputtering chamber do not raise any problem, and the deposited ITO film beside the PR has conventional ITO qualities. Furthemore, the particles th...

Dual-gate amorphous (a)-InGaZnO thin-film transistors (TFTs) are simply realized using the passivation layer of already fabricated bottom-gate TFTs as top-gate dielectric, so that an electrical biasing of either top or bottom gate may control the threshold behavior of the device. By applying a voltage to the top gate of a TFT that is serially connected to the next adjacent TFT, we could form a logic inverter with a decent voltage gain and desirable transition voltage, while a NOR logic circuit was also achieved by independent control of the dual gates. On the one hand, when both of the top and bottom gates are simultaneously controlled by single bias, our dual-gate TFT displays an excellent subthreshold swing property that leads to an excellent voltage gain in an inverter.

Lead sulfide (PbS) quantum dots (QDs) have great potential in optoelectronic applications because of their desirable characteristics as a light absorber for near-infrared (NIR) photodetection. However, most PbS-based NIR photodetectors are two-terminal devices, which require an integrated pixel circuit to be practical photosensors. Here we report on PbS QD/indium gallium zinc oxide (InGaZnO, IGZO) metal oxide semiconductor hybrid phototransistors with a photodetection capability between 700 and 1400 nm, a range that neither conventional Si nor InGaAs photodetectors can cover. The new hybrid phototransistor exhibits excellent photoresponsivity of over 106 A W−1 and a specific detectivity in the order of 1013 Jones for NIR (1000 nm) light. Furthermore, we demonstrate an NIR (1300 nm) imager using photogating inverter pixels based on PbS/IGZO phototransistors at an imaging frequency of 1 Hz with a high output voltage photogain of ~4.9 V (~99%). To the best of our knowledge, this report demonstrates the first QD/metal oxide hybrid phototransistor-based flat panel NIR imager. Our hybrid approach using QD/metal oxide paves the way for the development of gate-tunable and highly sensitive flat panel NIR sensors/imagers that can be easily integrated. A hybrid near-infrared photoinverter based on lead sulphide quantum (PbS) dots and InGaZnO that exhibits a high photogain has been made. PbS quantum dots have promising properties for near-infrared detection, but two-terminal devices based on them require an integrated pixel circuit. Now, Do Kyung Hwang at Korea University of Science and Technology and co-workers have demonstrated a hybrid near-infrared detector that employs PbS quantum dots to sensitize InGaZnO. The detector covers a wavelength range of 700–1,400 nanometres, which is not covered by conventional photodetectors. It also exhibits an excellent photoresponsivity of over 106 amperes per watt. The researchers consider that this approach will open up the way to develop highly sensitive, flat-panel near-infrared sensors and imagers that are both gate tunable and readily integrable. We propose hybrid approach of two classes of PbS QD as NIR light absorber and IGZO as the photogenerated charges acceptor/transport semiconductor to create phototransistor for near infrared (NIR) detection/imaging. Such hybrid phototransistor shows photodetection capability between 700 and 1400 nm. We demonstrate a NIR (1300 nm) imager using photogating inverter pixel based on PbS/IGZO hybrid phototransistor.

Polycrystalline SrTiO3 thin films have been prepared on Si(100) substrates by RF magnetron sputtering. The films were deposited at 400 degrees C and were annealed at 600 degrees C. The films had a dense microstructure with fine grains. The electrical properties of the films were dramatically controlled with annealing. From the result of the capacitance-voltage (C-V) characteristics the dielectric constant and the flat band voltage of the annealed films were measured to be 75 and -0.31 V, respectively. These oxide thin films with high dielectric constant are potentially useful in ULSI applications.

A palladium (Pd) nanogap-based thin-film has been connected to an electrically stable amorphous InGaZnO thin-film transistor, to form a hydrogen sensor demonstrating a dramatic sensing capability. As a result of the Pd connection to the transistor source, our sensor circuit greatly enhances the hydrogen-induced signal and sensing speed in the sense of output voltage, clearly resolving a minimum hydrogen content of 0.05%. When the nanogap-based Pd thin-film was connected to the transistor gate, an extremely limited hydrogen content of even less than 0.05% was visibly detected through gate voltage shifts. Our results exhibit the most promising and practical ways to sense extremely limited hydrogen contents, originating from two methods: transistor-to-Pd nanogap resistor and transistor-to-Pd nanogap capacitor coupling.

We have developed roll printing process for low cost TFT LCD fabrication. Pattern position accuracy which is the most important issue for successful printing process could be improved by remodeling the blanket structure and the physical property of PDMS. Through improving printing pattern accuracy, we were able to print all layers of TFT and CF on substrates and a 15 inch XGA TFT LCD panel adopting TN mode was successfully fabricated.