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For years, there has been a strong drive for sub-micron pixel development, in spite of reaching the visible light diffraction limit, because a smaller pixel pitch of CMOS image sensors (CISs) is inevitably required for ever-miniaturizing camera modules as mobile devices incorporate more cameras, few of which are dedicated to ultra-high-resolution zoomed images [1]. To that end, image sensor vendors have tried to find new ways to avoid reduction in sensitivity and more crosstalk in the sensor through pixel architecture change and/or fabrication process refinement [2] –[4]. For example, a $0.7 \mu m$ pixel sensor was demonstrated with acceptable photodiode (PD) full-well capacity (FWC) of $\gt 6$,000e- as well as signal-to-noise ratio (SNR) of $\sim32$ dB without optical/electrical crosstalk by employing state-of-the-art full-depth deep-trench isolations (FDTIs). [4] However, further scaling requires elaborate fabrication innovation and layout ideas. At the same time, meeting every aspect of pixel performance compared to the previous generation becomes even more difficult, e.g., with respect to dark or illuminated characteristics, fixed-pattern or temporal noises, etc. The latter, in particular, is associated with in-pixel source-follower (SF) amplifiers. Therefore, electrical performance of scaled in-pixel transistors cannot be overlooked. In this paper, a 32-megpixel (MP) CIS with $0.64 \mu m$ unit pixels is demonstrated with FDTI design. Innovations in terms of fabrication and design to achieve this performance with scaling are discussed.

In this study, we propose a method for improving the stability of multilayer MoS2 field-effect transistors (FETs) by O2 plasma treatment and Al2O3 passivation while sustaining the high performance of bulk MoS2 FET. The MoS2 FETs were exposed to O2 plasma for 30 s before Al2O3 encapsulation to achieve a relatively small hysteresis and high electrical performance. A MoOx layer formed during the plasma treatment was found between MoS2 and the top passivation layer. The MoOx interlayer prevents the generation of excess electron carriers in the channel, owing to Al2O3 passivation, thereby minimizing the shift in the threshold voltage (Vth) and increase of the off-current leakage. However, prolonged exposure of the MoS2 surface to O2 plasma (90 and 120 s) was found to introduce excess oxygen into the MoOx interlayer, leading to more pronounced hysteresis and a high off-current. The stable MoS2 FETs were also subjected to gate-bias stress tests under different conditions. The MoS2 transistors exhibited negligibl...

Various approaches have been proposed for point-of-care diagnostics, and in particular, optical detection is preferred because it is relatively simple and fast. At the same time, field-effect transistor (FET)-based biosensors have attracted great attention because they can provide highly sensitive and label-free detection. In this work, we present highly sensitive, epidermal skin-type point-of-care devices with system-level integration of flexible MoS2 FET biosensors, read-out circuits, and light-emitting diode (LEDs) that enable real-time detection of prostate cancer antigens (PSA). Regardless of the physical forms or mechanical stress conditions, our proposed high-performance MoS2 biosensors can detect a PSA concentration of 1 pg·mL–1 without specific surface treatment for anti-PSA immobilization on the MoS2 surface on which we characterize and confirm physisorption of anti-PSA using Kelvin probe force microscopy (KPFM) and tapping-mode atomic force microscopy (tm-AFM). Furthermore, current modulation induced by the binding process was stably maintained for longer than 2–3 min. The results indicate that flexible MoS2-based FET biosensors have great potential for point-of-care diagnostics for prostate cancer as well as other biomarkers.

It is becoming more important for electronic devices to operate stably and reproducibly under harsh environments, such as extremely low and/or high temperatures, for robust and practical applications. Here, we report on the effects of atomic-layer-deposited (ALD) aluminum oxide (Al2O3) passivation on multilayer molybdenum disulfide (MoS2) thin-film transistors (TFTs) and their temperature-dependent electrical properties, especially at a high temperature range from 293 K to 380 K. With the aid of ultraviolet-ozone treatment, an Al2O3 layer was uniformly applied to cover the entire surface of MoS2 TFTs. Our Al2O3-passivated MoS2 TFTs exhibited not only a dramatic reduction of hysteresis but also enhancement of current in output characteristics. In addition, we investigated the temperature-dependent behaviors of the TFT performance, including intrinsic carrier mobility based on the Y-function method.

We report a novel platform on which we design a flexible high-performance complementary metal–oxide–semiconductor (CMOS) inverter based on an inkjet-printed polymer PMOS and a two-dimensional (2D) multilayer molybdenum disulfide (MoS 2 ) NMOS on a flexible substrate. The initial implementation of a hybrid complementary inverter, comprised of 2D MoS 2 NMOS and polymer PMOS on a flexible substrate, demonstrates a compelling new pathway to practical logic gates for digital circuits, achieving extremely low power consumption with low sub-1 nA leakage currents, high performance with a voltage gain of 35 at 12 V supply voltage, and high noise margin (larger than 3 V at 12 V supply voltage) with low processing costs. These results suggest that inkjet-printed organic thin film transistors and 2D multilayer semiconducting transistors may form the basis for potential future high performance and large area flexible integrated circuitry applications.

ZnO thin films and nanowires (NWs) were precisely treated by focused electron-beam (E-beam) irradiation with a line width between 200 nm and 3 μm. For both ZnO films and NWs, an increased green emission was clearly observed for the E-beam-treated parts. Using a high-resolution laser confocal microscope, the photoluminescence intensities for E-beam-treated ZnO structures increased with increasing dose 1.0 × 1017–1.0 × 1018 electrons/cm2. The resistivity of a single ZnO NW increased from 56 to 1800 Ω cm after the E-beam treatment. From the results for the annealed ZnO thin films, we analyzed that the variations in PL and resistivity were due to the formation of vacancies upon focused E-beam irradiation.

In this study, a melt-blown nonwoven filter for medical masks was manufactured using an online hydrocharging system. The effects of basis weight (gsm) and die to collector distance (DCD) on the breathing resistanceand filtration efficiency were investigated. Hydro charging of the nonwoven web seemed to improve the filtering effi-ciency. However, it did not affect breathing resistance. It was demonstrated that the breathing resistance and filtrationefficiency increased with increasing gsm but decreased with increasing DCD. With a DCD of 19 cm, when the gsmincreased from 20 to 50 gsm, breathing resistance increased from 5.14 to 8.33 mmH 2 O and filtration efficiencyincreased from 81.39 to 94.98%. With a basis weight of 25 gsm, when the DCD increased from 15 to 25 cm, breath-ing resistance decreased from 7.38 to 4.27 mmH 2 O and filtration efficiency decreased from 89.56 to 68.28%. In addi-tion, it was demonstrated using stability tests that the hydro charging effect lasted for 13 weeks.Keywords: melt-blown nonwoven, hydro charging, medical mask, filtration efficiency, breathing resistance

In this study, 25gsm melt-blown polypropylene nonwoven for dust-proof/medical masks was finished by the corona discharging treatment. The influence of corona discharging parameters on the filtration efficiency was investigated. Several parameters such as discharging voltage, discharging speed, distance to discharging wire and configuration of discharging system had an effect on filtration efficiency, while the parameters had no effect on breathing resistance. Optimum corona discharging conditions are as follows: Wires were installed on the upper part of the nonwoven and paper pipe was installed on the lower part of the nonwoven having a distance of 5cm. The sequence of wire voltages was +60 kV, +60 kV, 0, -60 kV, and -60 kV. The discharging voltage and speed were 60 kV and 30m/min respectively. The nonwoven treated by corona discharging at the optimum condition showed a filtration efficiency of 80% or more, which is suitable for dust-proof/medical masks.

We report on the light-emitting color barcode nanowires (LECB-NWs), which were fabricated by alternating the electrochemical polymerization of light-emitting polymers with various luminescence colors and efficiencies. The nanoscale photoluminescence characteristics of LECB-NWs were investigated using a laser confocal microscope with a high spatial resolution. The alternating light emissions of the LECB-NWs showed orange-yellow, red, and green colors due to the serial combination of poly(3-butylthiophene), poly(3-methylthiophene), and poly(3,4-ethylenedioxythiophene), respectively, with distinct luminescence intensities. The optical detection sensitivity and stability of LECB-NWs have been enhanced through a nanoscale Cu metal coating onto the NWs, based on surface plasmon resonance coupling and protection against oxidation. The flexibility of the LECB-NWs has been investigated through the folding and unfolding of the NWs by an applied nanotip impetus. The flexible LECB-NWs can be used as highly sensitive optical identification nanosystems for nanoscale or microscale products with complex physical shapes.

We reported on the fabrication and nanoscale luminescence characteristics of the hybrid nanotubes (NTs) of light-emitting poly (3-methylthiophene) (P3MT) NT with gold (Au) nanoparticles (NPs) (P3MT/Au-NPs). After hybridizing the Au-NPs onto the surface of P3MT NTs, the light-emitting color of P3MT NTs was dramatically changed from a green to a bright red. From laser confocal microscope photoluminescence (PL) experiments for an isolated single strand of the NTs, we observed a ∼220 times enhancement of the PL peak intensity for the hybrid NT of P3MT/Au-NPs compared to that of the P3MT single NT. The enhancement PL efficiency of the hybrid NT of P3MT/Au-NPs can be explained in terms of a surface plasmon resonance (SPR) and nanoscale local electric field enhancement effects.

The percentage of those aged 60 and over is 43.5% among our country`s 3,186 thousands farming population, so farm village is getting aging society rapidly. Moreover agricultural competitiveness has being weakened due to labor shortage by degradation in quality of labor configuration from elderly porson. For realisms easy workability, we developed a motor vehicle for agricultural activity. The vehicle has an automatic guidance system which could follows a track of magnetic tape on the floor for easy moving to given working position. We collected data from two guidance sensors, located on front and rear end of the vehicle and calculated displacement and angle deviation from the track. This traveling system was stably controlled with processing information deflection S, angle of deviation, D and angle velocity, Vt

A new method for the tuning and enhancing photoluminescence (PL) characteristics of light emitting poly (3-methylthiopnehe) (P3MT) nanotubes through E-beam irradiation under atmospheric environments is reported. An E-beam generated from a linear electron accelerator (1 MeV, 1.6 × 10 13 -8.0 × 10 16 electrons cm -2 ) is irradiated onto P3MT nanotubes including an Al 2 O 3 template. From laser confocal microscope (LCM) PL experiments, significant enhancements in the PL intensity-up to about 90 times of an isolated single strand of the E-beam irradiated P3MT nanotubes-are observed. The luminescent color of the P3MT nanotubes changes from green to red color depending on the variation of E-beam dosage. These results might originate from the de-doping effect and the conformational modification through E-beam irradiations. Conformational changes of the E-beam irradiated P3MT nanotubes are confirmed by LCM single Raman and ultraviolet-visible (UV/Vis) absorption spectra. From UV/Vis absorption spectra, it is observed that the π-π* transition peak and the doping induced bipolaron peaks of the P3MT nanotubes dramatically vary with E-beam irradiating conditions.

We report on the synthesis and characteristics of polypyrrole (PPy) nanowires and poly(3-hexylthiophene) (P3HT) films by using functionalized single-wall carbon nanotubes (F-SWCNTs). The F-SWCNTs were prepared by the process of ultrasonication of SWCNTs mixture with nitric and sulfuric acid (3:1 volume ratio) solution. The F-SWCNTs has the pending carboxylic acid group ( COOH). The PPy nanowires and bulky P3HT film were electrochemically polymerized based on the Al2O3 nanoporous template and on the ITO glass, respectively, by using the F-SWCNTs as a dopant in electrolyte. We compared the structural characteristics between the arc-grown SWCNTs and the F-SWCNTs through a scanning electron microscope (SEM), a Fourier transform infrared (FT-IR) spectroscope, a Raman spectroscope, an X-ray photoelectron spectroscope, and an elemental analysis. The formation of PPy nanowires and bulky P3HT film were confirmed through SEM and FT-IR experiments.

Large-area and highly crystalline CVD-grown multilayer MoSe2 films exhibit a well-defined crystal structure (2H phase) and large grains reaching several hundred micrometers. Multilayer MoSe2 transistors exhibit high mobility up to 121 cm(2) V(-1) s(-1) and excellent mechanical stability. These results suggest that high mobility materials will be indispensable for various future applications such as high-resolution displays and human-centric soft electronics.

This study focused on finding the optimum conditions for displaying higher conductivity in an ATO-PET film prepared using the solvothermal method. The conductivity of the ATO film with Sb1.5:Sn8.5 increased to 800 °C calcinations. It did not, however, increase further even though the calcinations were at a temperature above 1000 °C. The average grain size measured from the FESEM micrographs was distributed within a 5.0-nm (at 400 °C) to 50.0-nm (at 1000 °C) range. It was determined from the XRD results that the special peaks assigned to the SnO2 tetragonal type dominated until 1000 °C in the ATO particles with Sb1.5:Sn8.5. It was also confirmed that the hydrophilicity (the T–OH/T–O ratio was larger) of the ATO nano-particle with Sb1.5:Sn8.5 was largest at 600 °C calcinations. Its binding energy remarkably increased at 1000 °C calcination. In various Sb:Sn mole ratios, the conductivity was at its best in ATO films (for Sb1.5:Sn8.5) with 600 °C calcinations, 9.0×105 (Ω/□). When 1,4-butanediol was used as a solvent, the conductivity of the ATO film was enhanced and the ATO film exhibited higher distribution than the other solvents did. The conductivity of the ATO film prepared in basic conditions (pH=10.0) was enhanced compared to those in acidic conditions.

Layered semiconductors with atomic thicknesses are becoming increasingly important as active elements in high-performance electronic devices owing to their high carrier mobilities, large surface-to-volume ratios, and rapid electrical responses to their surrounding environments. Here, we report the first implementation of a highly sensitive chemical-vapor-deposition-grown multilayer MoSe2 field-effect transistor (FET) in a NO2 gas sensor. This sensor exhibited ultra-high sensitivity (S = ca. 1,907 for NO2 at 300 ppm), real-time response, and rapid on–off switching. The high sensitivity of our MoSe2 gas sensor is attributed to changes in the gap states near the valence band induced by the NO2 gas absorbed in the MoSe2, which leads to a significant increase in hole current in the off-state regime. Device modeling and quantum transport simulations revealed that the variation of gap states with NO2 concentration is the key mechanism in a MoSe2 FET-based NO2 gas sensor. This comprehensive study, which addresses material growth, device fabrication, characterization, and device simulations, not only indicates the utility of MoSe2 FETs for high-performance chemical sensors, but also establishes a fundamental understanding of how surface chemistry influences carrier transport in layered semiconductor devices.

Space charge concentration due to fatigue cycles was examined with an adequate modeling in order to expect read/write endurance of a 64 Mbit one-transistor and one-capacitor (1T1C) ferroelectric random access memory (FRAM). For monitoring the change in space charge concentration according to fatigue cycles, we assumed that our ferroelectric capacitor is governed by a partially depleted Schottky conduction model. With this, the space charge concentration at the each decade of the fatigue cycles was calculated by measuring the current–voltage characteristics. The space charge concentration at the initial stage was evaluated into 1.95 ×1020 and 2.16 ×1020/cm3 after the 1011 cycles. The concentration of 2.29 ×1020/cm3 was expected at the fatigue cycles of 1016 through a linear regression of the concentration plot against fatigue cycles. Accordingly, it could be said that our ferroelectric capacitor has few problems of endurance up to the 1016 cycles considering the concentration of ~1020 and the film thickness of 80 nm. Other empirical data obtained in the capacitor level after full integration are supporting this expectation as well.

Various strategies and mechanisms have been suggested for investigating a Schottky contact behavior in molybdenum disulfide (MoS2) thin-film transistor (TFT), which are still in much debate and controversy. As one of promising breakthrough for transparent electronics with a high device performance, we have realized MoS2 TFTs with source/drain electrodes consisting of transparent bi-layers of a conducting oxide over a thin film of low work function metal. Intercalation of a low work function metal layer, such as aluminum, between MoS2 and transparent source/drain electrodes makes it possible to optimize the Schottky contact characteristics, resulting in about 24-fold and 3 orders of magnitude enhancement of the field-effect mobility and on-off current ratio, respectively, as well as transmittance of 87.4 % in the visible wavelength range.

The problem of accessing and managing digital contents scattered on personal portable devices such as smart phone, digital camera, MP3 player, or laptop in an integrated fashion is critical in ubiquitous computing. It is not trivially solvable because the underlying networks are dynamically configured and the data types supported by each device are constrained. Due to recent rapid growth in personal digital contents, it becomes a major issue. To address this challenge, we have proposed a self-managed distributed file services called PosCFS+ [1], [2], [3] in personal area networks (PAN). PosCFS+ automatically detects every devices available in PAN and integrates the storage space of all the devices into a virtual storage. In order to facilitate data access to the virtual storage, PosCFS+ creates virtual directories which enable a semantic file addressing from applications. However, in a real world consisting of multiple consumer electronics (CE) devices, it is not easy or even impossible to install software components like PosCFS+ in the CE devices because they are proprietary. In this paper, we present the design and implementation of a CE device agent which enables the storage virtualization by PosCFS+ on CE device ensembles. Most CE devices are connected to a host computer via USB interface, so the agent will be executed on the host computer to export the physical storage space of a CE device to PosCFS+. Then, virtual storages and virtual directories are created by PosCFS+ according to predefined user profile. Finally, to solve the problem of limited data type and format supported in a CE device, the event notification framework proposed in [3] is used for automatic data transcoding.

Conventional ɑ-Si:H phototransistors exhibit poor photosensitivity due to low photo-conversion efficiency. To overcome this intrinsic limit, we introduce gate underlap in ɑ-Si:H phototransistors and demonstrate photosensitivity enhancement. We show that photocurrent can be significantly larger than dark current by 4 orders of magnitude, using 1-μm gate underlap at incident optical power density (Pinc) of 3.2 W/cm2. Our 1-μm gate-underlap phototransistor exhibits higher photosensitivity than the device without gate underlap by 64 times with Pinc = 0.2 W/cm2 and a wavelength of 785 nm. Our gate-underlapped phototransistors also show excellent time-resolved photoswitching behaviors, demonstrating the great potential for highly sensitive photodetectors.

We report on the fabrication and nanoscale luminescence characteristics of an isolated rubrene single nanoparticle (NP). A solvent-vapor annealing process changed pristine rubrene NPs, prepared by a reprecipitation method, to perfect crystalline NPs. The formation and structural properties of crystalline and non-crystalline rubrene NPs were studied through SEM, HR-TEM, and X-ray diffraction experiments. The nanoscale photoluminescence (PL) characteristics and the luminescence color of the rubrene single NP were measured using a high-resolution laser confocal microscope with color charge-coupled device images. In comparison with the pristine rubrene NPs, the crystalline NPs exhibited highly bright and sharp light emission. The main PL peak at 561–562 nm for the crystalline rubrene single NP had a relatively narrow line-width and became more dominant through a solvent-vapor annealing. The enhanced and sharp light emission of the crystalline rubrene single NP originated from the strong π–π interaction of rubrene molecules along the major crystalline axis in the nano-sized structure.

During the device lifetime tests such as high temperature operational life (HTOL) and high temperature storage (HTS) tests, a physical de-lamination of the IrO2 layer in vertical conjunction to pulsed plate-line, so-called here additional top electrode (ATE), ATE has appeared and localized in specific cell arrays. This failure stems either from the reduction of IrO2 by the penetrated hydrogen at the interface between ATE Ir to top electrode (TE) Ir or from lack of dummy cells applied, or both. In the back end of line (BEOL), several heat treatments were introduced and then the reduction was reduced. It is essential to consider a deliberated anneal procedure in the BEOL integration. This is because otherwise case may provoke a contact failure in pulsed plate-line node of cell arrays. Also, we simulate stress distribution in cell arrays depending on how many dummy cells have been taken into account. The fluctuation of the stress projected on the IrO2 layer should be controlled uniformly by adding a certain number dummy cells.

We have developed an electromagnetic (EM) wave propagation theory through a single layer and multiple layers in the near-field and far-field regions, and have constructed a matrix formalism in terms of the boundary conditions of the EM waves. From the shielding efficiency (SE) against EM radiation in the near-field region calculated by using the matrix formalism, we propose that the effect of multiple layers yields enhanced shielding capability compared to a single layer with the same total thickness in conducting layers as the multiple layers. We compare the intensities of an EM wave propagating through glass coated with conducting indium tin oxide (ITO) on one side and on both sides, applying it to the electromagnetic interference (EMI) shielding filter in a flat panel display such as a plasma display panel (PDP). From the measured intensities of EMI noise generated by a PDP loaded with ITO coated glass samples, the two-side coated glass shows a lower intensity of EMI noise compared to the one-side coated glass. The result confirms the enhancement of the SE due to the effect of multiple layers, as expected in the matrix formalism of EM wave propagation in the near-field region. In the far-field region, the two-side coated glass with ITO in multiple layers has a higher SE than the one-side coated glass with ITO, when the total thickness of ITO in both cases is the same.