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Nickel hydroxide [Ni(OH)2] is an electrochemically-active material used for rechargeable batteries, electrochemical capacitors, and electrochromic devices. Although there have been some studies on Ni(OH)2 thin films deposited by sputtering, the Ni(OH)2 formation has not been fully confirmed. In this study, a Ni metal target was reactively sputtered in atmospheres of O2 and Ar + H2O at substrate temperatures of RT (RT, around 20 °C), −80 °C, and −170 °C, and the aging treatment effects in the air at RT were studied. From optical, X-ray diffraction, and IR absorption measurements, β-Ni(OH)2 thin films were found to be formed after aging the films deposited at −80 °C in Ar + H2O, however, NiO thin films were formed at RT. These results corresponded well with a thermodynamic consideration of Ni(OH)2. At −170 °C, mixed metal and oxide films were formed, presumably because of insufficient Ni oxidation.

The doping technique is vital for applying two-dimensional (2D) materials such as transition metal dichalcogenide (TMDC)-based field effect transistors (FETs), which can control the channel polarity and improve the performance. However, as conventional doping techniques for silicon-based FET are not suitable for 2D materials, the realization of heavy doping of TMDC materials is challenging, especially for n-type heavy doping. This study reports a simple, regioselective, controllable, and chemically stable heavy doping method for 2H-MoTe2 crystal via high-density laser irradiation. The polarity of the doping can be controlled by changing the irradiation environment. For the MoTe2-nFET, good performance with enhanced contact properties was obtained using the contact doping method via laser irradiation in a vacuum environment.

Tungsten oxide (WO3) and nickel oxide (NiO) are typical inorganic electrochromic (EC) materials. The color of WO3 changes from transparent to blue by reduction, whereas that of NiO changes from transparent to brown by oxidation. This study fabricated EC devices with an indium tin oxide (ITO)/WO3/NiO/ITO/Nafion/ITO structure. The WO3/NiO double layer and Nafion were used as the EC layer and electrolyte, respectively. The color of the device changed from blue to transparent and then to brown by varying the applied potential from −2.5 to +1.0 V and then to +2.0 V. The WO3 and NiO films were reduced at −2.5 V; the WO3 film was oxidized at +1.0 V, and both were oxidized at +2.0 V. The transmittance in the visible and near-infrared regions changed independently. Hence, the devices are considered applicable for dual-band EC smart windows.

A method is proposed to predict the power generation performance of a pyroelectric generator (PEG) for waste-heat recovery systems in which an external electric field is applied to a ferroelectric material in synchrony with rapid temperature changes. The net generated energy density N D of the PEG at any temperature and electric field is predicted for two thermal-electrical cycles (including the Olsen cycle). This is done by approximating the dependence of the polarization density on temperature and electric field using hysteresis loop measurements. The difference between the predicted and measured values of N D was less than 15%. This method could be used to screen promising candidate materials for PEGs.

In this study, the effect of growth of intermetallic compound (IMC) layer between Au-Sn solder and electroless Ni/immersion Au (ENIG) on the thermal resistance of a flip-chip (FC) light emitting diode (LED) package was investigated. Two IMC layers were formed at the interface of FC LED package, including Au5Sn and (Ni,Au)3Sn4 that were identified using a transmission electron microscopy (TEM). A thermal aging test was carried out at 200 °C for 1000 h to observe IMCs growth. After 1000 h, the (Ni,Au)3Sn4 thickness increased to about 1.5 µm and the thermal resistance of the FC LED package increased by 3.5 times compared to the initial thermal resistance of 2 K/W. As the (Ni,Au)3Sn4 grew, a calculation of thermal resistance also increased comparing to the initial aging test, thus, the growth of (Ni,Au)3Sn4 layer can be effective factor on the increase of thermal resistances of FC LED package.

Silver is known to exhibit the highest reflectance, however, it requires a protective coating at the surface due to its low durability. We studied durability under high humidity of Ag films where Ti or Al surface layer (1 or 3 nm thick) was deposited onto the surface of the Ag films by rf magnetron sputtering. The environmental test was carried out at 55 °C, 90% relative humidity for 16 h. After the test, considerable agglomeration occurred in the Ag single film, but not in Ti/Ag and Al/Ag films. Therefore, the passivation effect of the surface oxide nanolayer, which was formed by natural oxidation of the metal nanolayer, was confirmed. This effect also meant that the specular reflectance was kept high, even after the test. It is found that a Al (1 nm)/Ag film could maintain the highest reflectance among all the samples.

Nickel oxide is a promising electrochromic (EC) material, and it is a material that changes color upon undergoing electrochemical oxidation and reduction. In this study, we prepared nickel oxide thin films by sputtering a nickel metal target using water vapor (H2O) as a reactive gas, and investigated the effects of substrate cooling and water vapor flow ratio in the atmosphere of argon (Ar) gas, R H2 O = H2O/(Ar + H2O). High and constant target voltage and plasma emission peaks of Ni atoms were obtained up to R H2 O = 75% at ‒80 °C, indicating that the Ni target maintained a metallic state. The deposition rate increased with increasing R H2 O when the substrates were cooled, and a maximum deposition rate of 34.6 nm min−1 was obtained at R H2 O = 50%. The nickel oxide thin films that were formed in the metallic target mode showed high transmittance in the as-deposited state and good EC properties.

We propose an alternative method of determining the magnetic anisotropy field μ0 H K in ferro-/ferrimagnets. On the basis of the droplet nucleation model, there exists linearity between domain-wall (DW) energy density and in-plane magnetic field. We find that the slope is simply represented by μ0 H K and Dzyaloshinskii–Moriya interaction (DMI). By measuring the in-plane magnetic field dependence of the coercivity field, closely corresponding to the DW energy density, a robust value for μ0 H K can be quantified. This robust value can be used to determine μ0 H K over a wide range of values, overcoming the limitations caused by the small strength of the external magnetic field typically used in experiments.

Miniature microwave plasmas with diameters of approximately 1 mm were generated in high-pressure argon (0.1–5.0 MPa) using a microgap electrode. The microwave power required to sustain plasmas was 1–10 W, depending on the pressure. Strong electron-neutral bremsstrahlung emission, indicating an electron temperature of approximately 12000 K, was observed at high pressures (>1 MPa), and electron densities estimated from Stark broadening revealed high values on the order of 1023 m−3. The analysis confirmed that the coefficient for the pressure shift of the Ar I line at 696.5 nm reported by Copley and Camm can be extended to 5 MPa.

In this paper, we report a self-assembled multilayer flexible electrode fabricated by a roll-to-roll sequential deposition process. We assembled the multilayer thin films consisting of weak polyelectrolyte poly(ethylenimine) (PEI) and conductive polymer polyaniline (PANi) on a poly(ethylene terephthalate) (PET) substrate via a roll-to-roll sequential deposition process. This fabricated multilayer electrode film showed stepwised growth with an agglomerated structure in accordance with the increase in the bilayer number of (PEI/PANi). The conductivity, morphologies, absorbance, and transmittance of electrode films were investigated using the four-terminal probes unit for current–voltage (I–V) characterization, atomic force microscopy (AFM), field-emission scanning electron microscopy (FE-SEM), and ultraviolet–visible (UV–vis) spectrometry. The prepared multilayer flexible electrode film with the coating sequence of (PEI/PANi)30 showed high transmittance in a visible range and low surface roughness of ca. 9 nm. The resistance of the multilayer electrode film was measured to be ca. 10 kΩ. As the bilayer number of (PEI/PANi) increased from 10 to 30, the surface roughness and resistance of the multilayer electrode film decreased. These experimental results showed that the uniform and highly transparent conductive films were successively formed on a flexible PET substrate by a self-assembly roll-to-roll process.

Embedded system technology can improve electrical performance and reduce assembly cost compared with those discrete component technologies. In this paper, simulation and characterization of embedded capacitors will be presented. The embedded capacitors were simulated and characterized employing eight layered printed circuit boards. Fabrication process of multilayer embedded capacitors will be presented. Theoretical considerations regarding the embedded capacitors have been paid to understand the frequency dependent impedance behavior. Frequency dependent impedances, capacitances, and quality-factors of fabricated embedded capacitors were investigated. As a result, parasitic inductance was developed mainly through via holes and it has almost same value regardless of different capacitances. Frequency dependent capacitance values of fabricated embedded capacitors were well matched with those of simulated embedded capacitors. Temperature dependent capacitance and loss tangent of fabricated embedded capacitor were presented.

Dual-frequency capacitively coupled plasmas (DF-CCPs) have been used to control the ion flux by the high-frequency source and the ion bombardment energy onto the electrode by the low-frequency (LF) source separately. However, an increase in the LF voltage, which extends the maximum ion energy to a higher value, causes the reduction of the bulk plasma length with a subsequent decrease of the plasma density. By using a one-dimensional particle-in-cell/Monte Carlo simulation code, the effect of the magnetic field on a DF-CCP is investigated to find whether the plasma can be sustained during the LF voltage increase. It is found that a low magnetic field can effectively maintain the plasma density and electron temperature constant with respect to the variation of the LF voltage.

Due to the various advantages of the use of atmospheric pressure, recent studies on the ashing of organic materials are focused on the atmospheric pressure plasma rather than low pressure plasma. In this study, atmospheric pressure plasma was generated using dielectric covered electrodes and AC pulsed power supply (10 kV) driven at low frequency to remove organic materials on the surfaces of metal such as Cr. In such a configuration, the effects of process conditions and ashing gases on the ashing properties have been investigated. Nitrogen (N2) and oxygen (O2) were used for ignition and ashing, respectively. By adding small amount of O2 to N2, the photoresist ashing rate was increased due to the increment of oxygen radicals in the plasma. However, further addition of oxygen decreased the photoresist ashing rate, possibly because of the lower plasma density caused by the formation of negative ions between oxygen molecules and electrons in the plasma. Additionally, the effect of input voltage on ashing was investigated. The raised input voltage increased the ashing effect possibly due to the increased chemical reaction with organic materials resulting in the increased volatilization and detachment from the surface. In this paper, optimal process condition for gas flow rate and process gap will be discussed.

A new laser glass cutting technology using femtosecond and CO2 lasers is presented. Mechanical breaking after scribing using a femtosecond laser was evaluated and compared with the hybrid method for the cutting of flat panel display (FPD) glass. Various laser fluences were tested to determine the threshold energy and optimum grooving conditions without microcracks. The hybrid method was very effective for the FPD glass microfabrication and for performing full cutting without the mechanical breaking process. Consequently, it was found that the FPD panel was clearly cut using the method and the methodologies were very effective even for a mass-production cutting system.

In this article, the nonvolatile nano-floating gate memory (NFGM) device was fabricated with self-assembled metal-oxide nano-particles embedded in a polyimide gate insulator and characterized.

A novel complementary metal–oxide–semiconductor (CMOS) process compatible and self-aligned fabrication method for the dual-gate single-electron transistor (DG-SET) is presented. The performance of previous versions of the DG-SET was limited by inherent parasitic elements and its fabrication process was divergent from conventional CMOS, limiting the possibility of co-integration. Through simulation, the parasitic elements are confirmed to be caused by the non-self-alignment of the control gate, side gates, and source/drain. To resolve such issues, a new type of DG-SET was fabricated using a self-aligned process. Measurement results obtained at room temperature revealed clear Coulomb oscillation peaks in the trans-conductance curve. Through parameter extraction and its comparison with previous results, this is confirmed to be the consequence of single-electron tunneling. Also, in order to confirm that the single-electron tunneling is caused by the electrically induced tunneling barriers, and not by random fluctuations along the SOI active, low temperature measurement results for devices with different parameters is compared.

A new three-dimensional (3D) projection display system using two screens, one stacked in front of the other, has been developed. The front screen is made of a scattering polarizer film, and it either diffuse-reflects or transmits the incident light depending on the polarization state of the light. The near and far images are projected onto the front and rear screens, respectively, using light waves with mutually orthogonal polarization states. A clear image can be formed on the rear screen, and it is visible through the front screen over a wide range of viewing angles. It was found that the impression of depth is pronounced and that the eyestrain induced is comparable to that of two-dimensional (2D) display systems.

When ultrasound propagates on the surface of a layered substrate, the phase and group velocities of a surface acoustic wave (SAW) depend on the frequency, and the dispersion of the SAW can be obtained from its critical angles, for various frequencies. In the present work, a broadband SAW was generated by an oblique incident wave, and the wave reflected at the edge of a specimen was detected by a pulse–echo setup. Detected signals were decomposed into rf waveforms of different frequencies by digital filtering, and the critical angle was determined as a function of frequency. Two specimens with different coating thicknesses were investigated and the dispersion of the SAW was obtained. The results obtained in the present work showed good agreement with those in previous works.

A diode-pumped Q-switched Nd:YVO4 laser (λ=1064 nm) was used for the fabrication of plasma display panel (PDP) bus electrodes. In the experiments, with the maskless laser direct patterning of indium tin oxide (ITO) films, the laser-ablated ITO patterns showed the formation of shoulders at the edge of the ITO lines and a ripplelike structure with the etched bottom compared with the chemically wet-etched ITO patterns. Using a Q-switched Nd:YVO4 laser and a galvanometric scanning system, 500 mm/s with a 40 kHz repetition rate was found to be appropriate for application to PDP manufacturing. By dipping the laser-ablated ITO films in the chemical etching solution for 30 s at 50 °C, the shoulders were effectively removed without affecting the discharging properties of ac-PDP.

It is observed that the multi-mode cw blue-violet diode laser exhibits revival of interference when the interferometric path length difference is much greater than the coherence time of the laser and that the recurring interference peaks are separated by the same distance. We report that this unusual interference phenomenon can be used for high-resolution mode spacing measurement of the multi-mode cw blue-violet diode laser without using a high-resolution spectrometer.

We improved the light extraction efficiency of InGaN-based light-emitting diodes (LEDs) in which an n-type GaN layer was patterned onto a sapphire substrate with nano-sized SiO2 columns. Indium tin oxide thin layer deposition on a SiO2 layer followed by wet etching gives rise to oxide self-assembled clusters of 100–400 nm size and a subsequent SiO2 etching with an oxide mask results in SiO2 columns on an n-type GaN layer. The output power of the patterned n-GaN substrate (PNS) LED shows a 1.33 time increase compared with that of a normal LED without an n-GaN pattern when the total output power emitted in all directions from the packaging LED was measured under a current injection of 20 mA. The increase in output power from the PNS LED depends on the size of the SiO2 columns on the n-type GaN substrate.

Unique four-bit/cell polycrystalline silicon–oxide–silicon nitride–oxide–silicon (SONOS) devices with separated ONOs utilizing the vertical channel of a silicon pillar, denoted as silicon pillar vertical-channel SONOS (SPVC-SONOS) devices, were designed to increase memory density. A narrow charge distribution and improved data retention were achieved owing to the separation of the storage nitride layers. An analytical model of the transient characteristics for investigating the effects of the dielectric composition and the erase speed, which was dependent on the erase voltage, was developed. Floating nodes acting as a trap site were added in the nitride layer to simulate the program characteristics using the conventional device simulator medici. The channel hot-electron-injection program, Fowler–Nordheim tunneling erase, and reverse mode read characteristics were estimated to verify the operation of the novel four-bit/cell SPVC-SONOS devices. The proposed unique four-bit/cell SPVC-SONOS devices can be used to increase memory density.

This paper investigate how post-growth annealing of low-temperature grown GaAs (LT-GaAs) affects, the structural changes induced by the generation of point defects, as well as strain relaxation, the intensity and coarsening of As clusters with annealing, and the carrier recombination lifetime. The intensity and coarsening of As clusters is revealed by the analysis of bright field and high-resolution transmission electron microscopy (HR-TEM). The structural change is determined by the analysis of the intensity as well as a satellite reflection and a peak shift of the X-ray Bragg reflection. The investigation of the defect structures and the carrier lifetime change in the LT-GaAs are based on measurements of HR-TEM, X-ray, Hall, and terahertz spectrum. A systematic study of as-grown and post-growth annealed LT-GaAs reveals that the carrier lifetime is directly related to the intensity and distance of the As clusters. The electrical resistance of the LT-GaAs increases as the annealing temperature increases. A post-growth annealing condition was investigated for emitting and detecting terahertz signals and a photoconductive type dipole antenna was fabricated on the LT-GaAs.

ArF immersion lithography may be the best candidate for sub-60 nm device patterning. However, the polarization effect is the most prominent root cause for the degradation of the image quality in high numerical aperture (NA) immersion lithography as the feature size shrinks. Therefore, it is important to understand the polarization effect in the mask. It is common knowledge that a small mask pattern is considered as the wave guide of transmission light. The induced polarization effect shows the different aspects between the conventional mask and the attenuated phase-shift mask (PSM). In this paper, we considered the effects of polarization state as a function of mask properties. The aerial image depends on the polarization states induced by the mask. We evaluated the performances of the conventional mask and the attenuated PSM by using the Solid-ETM simulation and AIMSTM (Aerial Image Measurement System) tool along with real wafer printing.

A microelectromechanical systems (MEMS)-based, micro-optical fiber coupler to obtain a high power laser diode beam is integrated with a fiber rod lens and an array of SU-8 lenses, through each of which the laser beams emitted from the laser diodes are collimated vertically and horizontally, respectively, thus increasing the coupling efficiency. The fibers bundle and the laser diodes are assembled in one package on a silicon optical bench. The optical properties of the SU-8 lenses are suitable for high power laser diode application. The collimation of the beams passing the rod lens and the SU-8 lenses was confirmed. According to the simulation and experimental results, the coupling efficiency of the fiber coupler was increased by the insertion of the SU-8 lenses when the emitter width of the laser diode was wide.

For the reduction of the fabrication cost and processing time of AC plasma display panels (PDPs), an indium tin oxide (ITO) layer was patterned as the bus electrode by direct writing with a Nd:YVO4 laser (λ=1064 nm). In comparison with the chemically wet-etched ITO patterns, laser-ablated ITO patterns showed the formation of shoulders at the edge of the ITO lines and a ripple-like structure of the etched bottom. For the Q-switched Nd:YVO4 laser and a galvanometric scanning system, 500 mm/s with 40 kHz repetition rate was suitable for the application to PDP manufacturing. When the laser ablation was applied in the fabrication of a PDP test panel, the laser-ablated ITO patterns showed a higher minimum sustaining voltage than that of chemically wet-etched ITO patterns, which is assumed to be a result of the shoulders at the edge and the ripple-like bottoms. It is necessary to conduct more investigations and analyses on the cause of the problems in laser-ablated ITO patterns to optimize laser patterning.

We report integration of metal organic chemical vapor deposition (MOCVD) TiSiN barrier metal into 65 nm low-k dielectric (k=2.9) interconnects. Selective TiSiN barrier was formed along via trench wall using direct contact via (DCV) process and subsequent Ta incorporation into Cu was found to significantly improve electromigration (EM) reliability. Also, a large reduction of 0.1 µm via/line resistances is achieved. The proposed integration method allows MOCVD TiSiN usable as a barrier metal for the nano scale interconnects, taking advantages of high throughput and excellent step coverage of MOCVD process compared to other barrier processes.

An electrostatic discharge (ESD) protection device, the so-called N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high-voltage input/output (I/O) applications. A conventional NEDSCR device shows typical silicon controlled rectifier (SCR)-like characteristics with a high current immunity level. However, its extremely low snapback holding voltage and low on-resistance cause a linearity problem in the current immunity level, which obstructs adopting this device as an ESD protection device. Moreover, it may cause a latch-up problem during a normal operation. Our simulation analysis results that these disadvantageous NEDSCR device characteristics are cured by appropriate junction/channel engineering. Adding a P-type counter pocket source (CPS) implant enclosing source N+ diffusion is proven to increase the snapback holding voltage and on-resistance of the NEDSCR device, realizing an excellent ESD protection performance and a high latch-up immunity. Since the CPS implant technique does not change avalanche breakdown voltage, this methodology does not reduce available operation voltage and is applicable regardless of the operation voltage.

A new (12+1)-channel block-addressing driving method and a cost-effective drive IC have been successfully developed. The power consumption of the new block-addressing driving method is nearly 50% less than that of the conventional block-addressing method. The panel integrated dc/dc converter for the voltage of transistor-turning-off (Voff) enabled us to reduce the size and the manufacturing cost of the driver IC. On the basis of these technologies, a 1.89'' active-matrix liquid crystal display with 240 × RGB × 320 pixels was fabricated with a data driver, a dc/dc converter for Voff, a gate driver, and a level shifter for a gate driver. The power consumption of the panel using the low-voltage driving liquid crystal is typically 13 mW.

We describe the importance of the functional group density of polymeric insulators (PI) for organic thin-film-transistors (OTFTs) in terms of the insulator processing temperature and the exposure of a linearly polarized ultraviolet (LPUV) light. The PI layers processed at lower temperatures than the boiling temperature (Tb) of the solvent have higher densities of functional groups than those processed above Tb. The carrier mobility in the pentacene OTFT processed below Tb increases at least by a factor of three with maintaining other electrical properties such as the threshold voltage and the current on/off ratio. Our results suggest that the preferential alignment of the pentacene molecules is not the main physical mechanism for the mobility enhancement. From the mobility anisotropy resulting from the polarization of the LPUV, the packing density of the pentacene molecules on the PI layer, dictated primarily by the density of functional groups, is found to play a critical role on the magnitude of the mobility.

Metal oxide nanoparticles are embedded in a polyimide matrix by a chemical reaction between a metal thin film and polyamic acid. The electrical characteristics of ZnO nanoparticles are investigated with a floating gate capacitor structure by capacitance–voltage (C–V) measurement. The C–V characteristics resulting from metal deposition modulation and the existence of a SiO2 layer are also investigated. As a result, ZnO particles with a SiO2 tunneling barrier show a C–V hysteresis voltage gap of 2.8 V at 300 K. ZnO particles directly located on a Si substrate show a C–V hysteresis width of 1.5 V at 80 K. This electrical characterization is discussed for applications to nano floating-gate memory devices.

It was investigated the current on a biased target in the non-uniform plasma. The argon plasma was generated at the low pressure of 0.5–5 mTorr and the stainless steel target was biased with 0.2–6 kV negatively. The target current increases with increasing the target voltage due to the non-uniform plasma distributed near the target, which follows the Child law. The secondary emission current, following the square root of target voltage, is superposed to the ion current. For the higher pressures of larger than 1.5 mTorr, the target current is larger than the expected current of Bohm current plus the secondary emission current. The deviation increases drastically with increasing the operating pressure, which may due to the local ionization near the target. This phenomenon is important to understand more accurately the high voltage sheath formation in practices.

Unique NAND flash memory cells with a booster line structure were designed to increase the channel voltage of a program-inhibited cell during program cycles. When a program voltage was applied to the selected word line, booster-line voltage coupled with control gate potential induced a high voltage in a program-inhibited channel. Because the turning on of the unselected cells was initiated by the booster line during programming, an unselected word line was maintained in the floating state without applying a pass voltage. Program disturbance in the NAND flash memory cell was decreased using a booster-line boosting scheme, and the cell's pass disturbance was effectively eliminated. The proposed unique NAND flash memory cell with a booster line can be used to improve the reliability of nanoscale NAND flash memories.

The feasibility of applying ZrO2Hx thin films as solid electrolytes in solid-state ionic energy systems, such as solid oxide fuel cells and supercapacitors was studied. ZrO2Hx thin films were deposited on Pt/Ti/SiO2/Si substrates by radio-frequency reactive sputtering with various hydrogen volume fractions in reactive gas. With a variation in hydrogen volume fraction, the surface roughness of the as-deposited films increased. In addition, the structure of the as-deposited films grew in the [111] direction with an increase in hydrogen volume fraction. By Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) studies, the Zr/O ratio and hydrogen distribution were evaluated. On the basis of a sample structure of Pt/ZrO2Hx/Pt/Ti/SiO2/Si for measuring an electrochemical property, an impedance measurement conducted at room temperature revealed an ionic conductivity of 1.67 ×10-6 S/cm, suggesting that ZrO2Hx thin films can possibly be used as solid oxide thin film electrolytes in all solid-state ionics power devices requiring a hydrogen conducting electrolyte.

Color indicating film to detect ethylene (C2H4) gas was fabricated by depositing SiO2 nanoparticles and the indicating solution synthesized with palladium sulfate as well as ammonium molybdate on the filter paper. The color of indicating film without SiO2 was easily changed from white to blue in air because PdSO4 remarkably accelerates the redox reaction of ammonium molybdate, which generates molybdenum blue reaction. In this study, we successfully diminished the color change of indicating film in air by controlling the amount of SiO2 on filter paper using a layer-by-layer (LBL) self-assembly method. The color of prepared indicating film with 30 PDDA/SiO2 bilayers was maintained to be white in air. When this indicating film was exposed to C2H4 (50–150 ppm), the Hunter values (L, a, and b) were gradually decreased until 8 days and then maintained. The color of indicating film was changed from white to dark blue.

Iron thin films were grown directly on n-Si(111) substrates by pulsed electrodeposition in a non-aqueous 0.1 M FeCl2 electrolyte solution. In this solution, Fe2+/Si interface showed a good diode behavior by forming a Schottky barrier. From single-step potential experiment in the potential ranges from 1.0 to 1.4 V, the formation of Fe nuclei in the early deposition stages was proceeded according to the three dimensional (3D) instantaneous nucleation followed by diffusion-limited growth rather than a progressive one. When depositing Fe using pulse potentials with the maximum voltage of 1.0 and 1.5 V, it was found that nucleation mechanism of Fe is similar with the results for the case of single-step potential experiment. However, nucleation during depositing Fe at 2.0 V initiated according to the progressive mechanism. Fe thin films, which obtains from pulse potential of 1.4 V with a frequency of 300 Hz, revealed a highly oriented columnar structures perpendicular to the surface of Si(111) and that only the single phase α-Fe(110) was grown on Si(111) substrate.

We report on the electrical and interfacial properties of nonalloyed Ti/Au ohmic and Pt Schottky contacts on Zn-terminated n-ZnO (1.5×1017 cm-3). Nonalloyed Ti/Au and Pt contacts on the Zn-terminated ZnO respectively exhibit ohmic and Schottky behavior owing to different work functions and out-diffusion characteristics. The nonalloyed Ti/Au contact reveals very linear current–voltage behavior with a specific contact resistivity of 2.2×10-5 Ω cm2. However, Pt contact shows Schottky behavior with Schottky barrier heights (SBHs) of 0.62 eV and 0.78 eV, obtained from current–voltage (I–V) and capacitance–voltage (C–V) measurements, respectively. Using Auger electron spectroscopy (AES), we correlated the electrical properties of the nonalloyed Ti/Au ohmic and Pt Schottky contacts with the properties of the interface between the metal and ZnO.

We propose a novel electrochemical detector (ECD) to catalyze redox efficiently by electrodepositing Prussian blue (PB, ferric hexacyanoferrate) on the indium tin oxide (ITO) electrode. Capillary electrophoresis (CE) and amperometric methods were used. We investigated the PB surface properties by topography from atomic force microscopy (AFM). The PB film on dense and smooth surfaces could catalyze redox reaction efficiently. Compared with CE-ECD microchips using a bare-ITO electrode, the proposed CE-ECD microchip using a PB modified electrode has shown better sensitivity of the electropherograms. It has been verified that wide-ranging detection can be performed under the limits of 0.01 mM of dopamine and catechol respectively when we use a PB modified electrode.

Ferromagnetic Zn1-xCuxO (ZnO:Cu) films were epitaxially grown on n-GaN(0001)/Al2O3(0001) by radio-frequency magnetron sputtering at a substrate temperature as low as 700°C. X-ray diffraction θ-2θ scans, -scans, and surface morphology studies revealed the degree of crystallinity, epitaxiality, and grain size. The full-width at half-maximum of the peak for the ZnO:Cu films deposited on GaN was below 0.18° according to ω-scans. The chemical bonding states and depth profiles of the films were investigated by X-ray photoelectron spectroscopy (XPS) and with a glow discharge spectrometer (GDS). A magnetic property measurement revealed that Cu-doped ZnO films exhibit ferromagnetic behavior with a strong exchange interaction between sp-band carriers and localized d electrons at room temperature.

We have used liquid-delivery metal-organic chemical vapor deposition (LD-MOCVD) to grow polycrystalline CoxTi1-xO2 anatase films on SiO2/Si substrates. A scanning Auger microscope (SAM) technique is introduced to obtain the elemental mapping images from the Co-doped TiO2 film. The existence of Co-rich complex oxide compound was identified from an elemental distribution of the annealed film. The magnetic distribution of the film was investigated using a magnetic force microscope (MFM). The co-existence of Co-metal states with Co-oxide compounds at the surface region of the film were investigated by narrow-scans of X-ray photoelectron spectroscopy (XPS).

We investigate light transmission of Ag nano protrusions with a scanning near-field optical microscope (SNOM) to study the surface plasmon (SP) in metallic films. A Ag nanoprotrusion whose height is ~20 nm is fabricated by the deposition of Ag on the Ti nano-protrusion template which is made by nano-oxidation with an atomic force microscope (AFM). It is found that through several scans, the tip is coated with Ag from the sample, and this modified tip shows apparent undulation patterns in SNOM imaging, while a fresh tip does not. The undulation pattern in the SNOM image is observed only along the direction of polarization light close to the expected undulation period. This result indicates that local launching of SP is effective with an Ag-coated tip and the SP launching characteristic is consistent with the so-called cos 2? SP distribution. By finite domain time difference (FDTD) simulations, it is confirmed that light transmission is enhanced in the Ag-coated tip compared to the fresh tip. Our results imply that local illumination with a noble-metal-coated cantilever probe tip is desirable for obtaining more detailed features in SNOM images involved with SP. Our results also indicate that a nano protrusion fabricated by AFM-based nano-oxidation can be applied to an optical element using surface plasmon.

Various types of barrier ribs for a plasma display panel were formed via a capillary molding process. A thermosetting paste was filled into cavities of working molds by means of capillary action and was cured prior to removal of the molds. The working molds were prepared by curing liquid polydimethylsiloxane on master molds that were produced from a photoresist. It was demonstrated that various types of barrier ribs could be produced successfully by sintering the ribs formed by the molding process. In addition, the effects of solid loading in the paste, prefiring temperature and type of barrier ribs on the morphologies of the ribs were investigated.

The fiber-to-planar waveguide (PWG) couplers with two vertically separated metals films have been proposed, and theoretical and experimental investigation of the behavior of the coupler have been presented. Based on the normal-mode theory, the influence of the structural parameters on the characteristics of the device was analyzed and explained. The measured behavior of the device was in good agreement with theoretical predictions. Depending on the structural configuration, the device behaved as either a narrower filter or a polarizer. The possibility of its application as an active component has also been examined.

In this study, an investigation for the degradation of p+ to p+ isolation characteristics in a high voltage process with shallow trench isolation was carried out. It could be explained that the degradation phenomenon was caused by carrier injection. In order to improve this, the results of p+ to p+ isolation degradation were determined under different ion implantation conditions and depths and widths of isolation. From these results, it was found that carrier injection mainly occurred at the sidewall of a trench, and the interface trap between Si3N4 and SiO2 was considered to be a dominant factor based on the result of degradation reduction with increasing thickness of sidewall oxide. Consequently, the improvement of the p+ to p+ isolation degradation caused by carrier injection could be achieved by optimizing the dose of a masked lightly doped drain and a field implantation energy.

The oxidation behaviors of Ti–Si–N coating layers were investigated in terms of Si content and their characteristic microstructures. The Ti–Si–N films were characterized as composites of fine TiN crystallites and amorphous Si3N4 phase. The continuity of amorphous Si3N4 phase, i.e., the degree of encapsulation of TiN crystallites by amorphous Si3N4 phase, was an important key factor governing the oxidation behavior of Ti–Si–N coating layers. In the case of Ti–Si–N coating layers containing 4 at.% Si, TiN crystallites were not fully surrounded by the amorphous Si3N4 phase due to the insufficient amount of Si3N4 and the relatively large TiN crystallites size. Hence, the Ti–Si–N coating layers contained 4 at.% Si fast oxidized through TiN crystallites above 600°C. However, Ti–Si–N coating layers containing the Si content above 10 at.% showed much improved oxidation resistance even above 800°C because it had the finer TiN crystallites, and these TiN crystallites were fully surrounded by amorphous Si3N4 phase. The oxidation rate dependence on the Si content, and in particular the microstructure of Ti–Si–N film as derived from Si content, was systematically studied in this work.

We propose novel polycrystalline silicon thin-film transistors (poly-Si TFTs) to reduce leakage current effectively by employing the offset region near the drain and extended gate electrodes. The active layer has been prepared by two-step-annealing, which is combination of solid phase crystallization and excimer laser annealing (ELA). In the proposed devices, we have employed novel gate insulator structure, which forms the offset region and the extended gate electrodes. According to the experimental results, the leakage current of the proposed TFTs is reduced by more than a magnitude of two orders, compared with that of conventional TFTs, while ON current remains almost the same. It is verified by means of a device simulator that the electron concentration in the offset region increases under the ON state and decreases under the OFF state due to the extended gate electrodes and offset region.

Single-mode P–p–n–N InGaAsP/InP ridge waveguide phase modulators have been fabricated and investigated at 1.55 µm. The ridge waveguide structure has been designed using a finite element method, grown by metal-organic-chemical-vapor-deposition (MOCVD), and fabricated by chemical wet etching. Their phase modulation characteristics were measured by using the Fabry–Perot resonance method with a tunable laser. The measured phase modulation efficiency for a 2-mm-long device was determined to be as high as 34 deg/Vmm for the TE mode. This value corresponds to the highest experimental electrooptic modulation efficiency reported thus far for InGaAsP/InP DH-type phase modulators at the said wavelength region.

The electrical properties of lanthanum oxide was grown by using metal organic chemical vapor deposition (MOCVD) were investigated from the change of structural properties which occurred during the post-annealing process. The as-grown film had a dielectric constant of 18.8, and capacitance equivalent oxide thickness of 1.7 nm. The leakage current density of the film was measured as 2.4×10-4 A/cm2 at -1 MV/cm. When the film was annealed at 900°C, the dielectric constant decreased with the increase of the interfacial layer.

Electrooptical (EO) characteristics of a new multidomain vertical-alignment (MVA) liquid crystal display (LCD) with negative dielectric anisotropy on a homeotropic photopolymer were studied. Good voltage-transmittance (V-T) curves of the new MVA-LCD on the homeotropic photopolymer were obtained. Also, the stable response time of the new MVA-LCD on the homeotropic photopolymer was achieved. The viewing angle of the new MVA-LCD could be improved by a crossed stripe grating-groove surface as the alignment layer using a photolithograph method on the photopolymer.