Choon-Sang Park

High performance 5nm radius Twin Silicon Nanowire MOSFET (TSNWFET) : fabrication on bulk si wafer, characteristics, and reliability

For the first time, we have successfully fabricated gate-all-around twin silicon nanowire transistor (TSNWFET) on bulk Si wafer using self-aligned damascene-gate process. With 10nm diameter nanowire, saturation currents through twin nanowires of 2.64 mA/mum, 1.11 mA/mum for n-channel TSNWFET and p-channel TSNWFET are obtained, respectively. No roll-off of threshold voltages, ~70 mV/dec. of substhreshold swing (SS), and ~20 mV/V of drain induced barrier lowering(DIBL) down to 30 nm gate length are observed for both n-ch and p-ch TSNWFETs

Experimental Observation of Halo-Type Boundary Image Sticking in AC Plasma Display Panel

Infrared-emission observations show that the discharge characteristics related to the MgO surface are improved in both the image sticking and boundary image sticking cells, whereas luminance observations show a deterioration in the visible-conversion characteristics related to the phosphor layer in both the image sticking and boundary image sticking cells. Consequently, the image sticking phenomenon is strongly related to the Mg species sputtered from the MgO surface of the discharge cells due to an iterant strong sustain discharge. In particular, halo-type boundary image sticking is due to the redeposition of Mg species on both the MgO and phosphor layers in the nondischarge region adjacent to the discharge region, as confirmed by Vt close curve, time-of-flight secondary ion mass spectrometry, and scanning electron microscope analyses.

Driving waveform for reducing temporal dark image sticking in AC plasma display panel based on perceived luminance

Minimizing the reset discharge produced under an MgO-cathode condition and eliminating the wall charges accumulated on the address electrode prior to the reset period are the key factors involved in reducing temporal dark image sticking. Thus, based on the perceived luminance, new driving waveforms that can prohibit an MgO-cathode induced reset discharge or erase the wall charges accumulated on the address electrode prior to the reset period are examined for the complete elimination of temporal dark image sticking without deteriorating the address discharge characteristics. As a result of monitoring the difference in the infrared emission and perceived luminance between the cells with and without image sticking, the proposed driving waveform was shown to effectively remove temporal dark image sticking without deteriorating the address discharge characteristics

Influence of Ion Bombardment on Electron Emission of MgO Surface in AC Plasma Display Panel

The influence of ion bombardment during a sustain discharge on the electron emission of the MgO surface and related driving characteristics of an ac plasma display panel were examined using the cathodoluminescence technique and SIMS analysis. The experimental results showed that severe ion bombardment predominantly sputtered Mg species from the MgO surface, thereby lowering the intensity of the F+ center peak to 3.2 eV due to the elimination of the oxygen vacancy and finally increasing the formative address delay time (Tf) due to an aggravated electron emission capability. Meanwhile, severe ion bombardment also destroyed the shallow trap level, thereby lowering the intensity of the shallow peak to 1.85 eV and eventually increasing the statistical address delay time (Ts) due to a poor electron emission capability from the shallow level. Finally, the aggravated electron emission capability from the shallow level resulted in a reduced wall voltage variation during the address period.

Mechanism and reduction of temporal image sticking in ac plasma display panel

It is found that temporal image sticking in ac plasma display panels (PDPs) is predominantly induced by organic impurities, such as CxHy, on the MgO surface. The vacuum ultraviolet produced during a short sustain discharge dissociates these organic impurities, such as CxHy, into C and H, where the latter then combines with the O from the MgO surface, resulting in the production of chemical compounds, including H2O, that lower the luminance by hindering the visible conversion of the phosphor layer. Thus, according to this mechanism, minimizing the residual organic impurities, such as CxHy, on the MgO surface is a key factor for removing temporal image sticking. Therefore, to reduce the residual impurity level on the MgO layer of a 50 in. full-high definition (HD) ac-PDP with an He (35%)-Xe (11%) content, the MgO layer is given rf-plasma treatment using various gases, and the experimental results show that Ar plasma treatment was most effective in eliminating the residual impurities on the MgO layer and the...

Prevention of Boundary Image Sticking in an AC Plasma Display Panel Using a Vacuum Sealing Process

Boundary image sticking can be inherently prevented in an ac plasma display panel fabricated using a vacuum sealing process. The results indicate that residual impurities, such as nitrogen or oxygen, are essentially related to the production of boundary image sticking. When checking the production of boundary image sticking in a test panel fabricated using a or an flow during the vacuum sealing process, no boundary image sticking appeared in the case of a flow, whereas boundary image sticking was produced with an flow, although the test panel was fabricated using a vacuum sealing process. Consequently, reducing the residual impurity, particularly oxygen, based on a vacuum sealing process can inherently prevent boundary image sticking.

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES) techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and gel permeation chromatography (GPC) techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw), about 533 kDa with 1.9 polydispersity index (PDI). This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

Conductive Polymer Synthesis with Single-Crystallinity via a Novel Plasma Polymerization Technique for Gas Sensor Applications

This study proposes a new nanostructured conductive polymer synthesis method that can grow the single-crystalline high-density plasma-polymerized nanoparticle structures by enhancing the sufficient nucleation and fragmentation of the pyrrole monomer using a novel atmospheric pressure plasma jet (APPJ) technique. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM) results show that the plasma-polymerized pyrrole (pPPy) nanoparticles have a fast deposition rate of 0.93 µm·min−1 under a room-temperature process and have single-crystalline characteristics with porous properties. In addition, the single-crystalline high-density pPPy nanoparticle structures were successfully synthesized on the glass, plastic, and interdigitated gas sensor electrode substrates using a novel plasma polymerization technique at room temperature. To check the suitability of the active layer for the fabrication of electrochemical toxic gas sensors, the resistance variations of the pPPy nanoparticles grown on the interdigitated gas sensor electrodes were examined by doping with iodine. As a result, the proposed APPJ device could obtain the high-density and ultra-fast single-crystalline pPPy thin films for various gas sensor applications. This work will contribute to the design of highly sensitive gas sensors adopting the novel plasma-polymerized conductive polymer as new active layer.

Reduction of permanent image sticking in ACPDPs using RF-plasma pretreatment on MgO surface

— The characteristics of the MgO layer are known to be an important parameter that affects the permanent image sticking or lifetime of an ACPDP. In this paper, to reduce the permanent image sticking in ACPDPs, the effects of RF-plasma pretreatments of the MgO layer on the permanent image sticking are investigated. The treatment was conducted by using several plasma-forming gases, including Ar, Ar followed by O2, and O2 followed by Ar. Measurements of luminance, normalized luminance, Vt closed curve, haze, MgO hardness, and photoluminescence between the discharge and nondis-charge regions under dark and bright backgrounds indicated that the plasma treatments of MgO using either Ar or Ar followed by O2 gases reduce the permanent image sticking on dark and bright images in an ACPDP.

Discharge Characteristics of AC Plasma Display Panel Prepared Using Vacuum Sealing Method

The base vacuum level achieved before loading the discharge gas is known to be an important parameter that affects both the address and sustain discharge characteristics in an AC plasma display panel (PDP), as a higher base vacuum level improves the discharge characteristics. Accordingly, the vacuum sealing method, which can enhance the base vacuum level, is adopted to enhance the MgO characteristics by reducing any residual gas impurity. The resulting changes in the address and sustain discharge characteristics, including the secondary electron coefficient, firing voltage, and dynamic voltage margin, are then compared with the results when using conventional atmospheric-pressure sealing for a 42-in ac PDP with a high Xe (11%) content. The vacuum sealing method was found to improve the secondary electron emission coefficient, lower the firing voltage, particularly under MgO cathode conditions, and increase the dynamic voltage margin. However, the vacuum sealing was also found to deteriorate the visible transmittance of the dielectric layer in the front panel. Nonetheless, the vacuum sealing process enabled the use of a higher Xe content, which is up to 17%, under a stable dynamic margin voltage, thereby improving both the luminance and luminous efficiencies of the AC PDP.