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We used Brewster's Law to examine the mechanism of liquid crystal (LC) alignment on an organic insulation layer when subjected to ion-beam irradiation. Brewster's Law implies that the maximum rate polarized ray on a slanted insulation layers on the substrate and it illustrates the dependence of polarization and the mechanical structure on the ion beam irradiation process. The pretilt angle of nematic LCs on the organic insulation surface was about 1.13° for an ion beam exposure of 45° for 1 minute at 1800 eV. This shows the dependence of LC alignment on the polarization ratio in a slanted organic insulation layer. We also discussed the electro-optical characteristic of twisted nematic (TN) LCD using ion beam irradiation on organic overcoat layer. [ABSTRACT FROM AUTHOR]

We investigated the use of nickel oxide (NiO) as a catalyst for the metal-induced crystallization. SiNx serves as a diffusion filter that forms an effective barrier to Ni and also acts as a passivation layer for metal contaminants. The NiO has a constant area density of 8.22×106 Ni atoms cm-2. This allows enough depletion regions for the growth of disklike grains. The thin film transistor exhibited a field-effective mobility of 15.9 cm2 V-1 s-1, a threshold voltage of -5.2 V, an Ion/Ioff ratio of 1.6×107, and a gate voltage swing of 0.8 V/decade. [ABSTRACT FROM AUTHOR]

We investigated the characteristics of a solution-processed indium-doped zinc oxide (In:ZnO) film formed via ion-beam (IB) irradiation as a liquid crystal (LC) alignment layer. The In:ZnO film was deposited using solution processing and cured at various temperatures. Uniform LC alignment was observed at all curing temperatures in cross-polarised optical microscopy images. A regular pre-tilt angle supported these results and showed homogeneous LC alignment. Several surface analyses were conducted to evaluate the effect of IB irradiation on the In:ZnO film surface. X-ray diffraction analysis showed an amorphous structure both before and after IB irradiation, and physical surface reformation was observed using atomic force microscopy. Root mean square surface roughness was reduced and a smooth surface was achieved after IB irradiation. X-ray photoelectron spectroscopy was used to detect chemical surface reformation. It was found that the IB irradiation broke the metal-oxide bonds and increased the occurrence of oxygen vacancies, which affected the van der Waals forces between the LC molecules and the In:ZnO film surface. Electrical performance was observed to identify the possibility of using the In:ZnO film in LC applications. Enhanced electro-optical performance was measured and zero residual DC voltage which was verified using a capacitance-voltage curve was achieved. [ABSTRACT FROM AUTHOR]

We present the fabrication of an anisotropic structure on a polyurethane (PU) film for aligning liquid crystal (LC) molecules with ion beam (IB) irradiation at an incident angle. The obtained anisotropic structure assembles the LC cells in a layer that aligns LC molecules uniformly. Polarised optical microscopy images of an LC cell fabricated with IB-irradiated PU were captured to confirm the LC alignment state and compared with those fabricated with non-treated PU. To analyse the effects of the IB irradiation, X-ray photoelectron spectroscopy and field-emission scanning electron microscopy were used to investigate the chemical and morphological modifications, respectively. IB irradiation modifies the chemical structure of PU, which indicates that a new skin layer is formed on the PU films. This skin layer generates an in-plane compressive strain, thereby creating buckles on the PU films. Simultaneously, the physical collision of the reactive Ar+ ions during IB irradiation induces a directional strain on the surface, thereby forming a unidirectional structure of buckles along the direction of IB irradiation. The PU film annealed at 200°C showed the high average transmittance of 88.9%, which is appropriate as an alignment layer. [ABSTRACT FROM AUTHOR]

In this study, transparent polystyrene (PS) was replaced with conventional polyimide material. As a non-contact process, an ion beam (IB) bombardment process was applied to align the homogeneous liquid crystal (LC) material on the PS surfaces. Confirming the atomic force microscopy and X-ray photoelectron spectroscopy analysis, the chemical compositional changes of the IB-irradiated PS surfaces were determined as a function of the IB exposure angle although there was no effect of modulation of the physical geographic characteristics on IB-irradiated PS surfaces. Using this analysis, the optimal IB bombardment condition was determined at the IB exposure angle of 45°. Finally, the electro-optical properties of an LC cell suggest the use of PS in conventional LC alignment materials. [ABSTRACT FROM AUTHOR]

We studied homogeneous liquid crystal (LC) alignment properties on ion-beam (IB) irradiated TiO2 films deposited by the electron beam evaporation method. Stable homogeneous LC alignment on a TiO2 surface resulted from IB irradiation energy over 1800 eV. X-ray photoelectron spectroscopy analyses showed that Ti4+ 2p3/2 and Ti4+ 2p1/2 peaks were increased with increasing IB energy. Assuming that the increased peaks produced anisotropy dipole fields in the direction of the IB exposure process, we confirmed that the increasing IB energy induced strengthened the surface energy for entirely clear and stable LC molecule orientation. The voltage-transmittance characteristics of the twisted-nematic cell on the TiO2 surface indicate that the TiO2 film has potential for use as the LC alignment layer. [ABSTRACT FROM AUTHOR]

The aligned liquid crystals (LCs) display on SiNx thin films using ion-beam (IB) irradiation was studied with controllability of pretilt angle depending on incident energies of the IB. The LCs alignment property for the SiNx thin films were observed to verify the practical application potential. A good LCs alignment of vertical alignment LCs cells on SiNx thin film surfaces irradiated with incident IB energy of 1800 eV was achieved. The atomic force microscopy (AFM) images of LCs on SiNx thin film surfaces irradiated with IB energy was used for the surface analysis. [ABSTRACT FROM AUTHOR]

The aligned liquid crystals (LCs) display on SiNx thin films using ion-beam (IB) irradiation was studied with controllability of pretilt angle depending on incident energies of the IB. The LCs alignment property for the SiNx thin films were observed to verify the practical application potential. A good LCs alignment of vertical alignment LCs cells on SiNx thin film surfaces irradiated with incident IB energy of 1800eV was achieved. The atomic force microscopy (AFM) images of LCs on SiNx thin film surfaces irradiated with IB energy was used for the surface analysis. [ABSTRACT FROM AUTHOR]

We investigated liquid crystal (LC) alignment as a function of ion beam (IB) incident angles and electro-optical (EO) characteristics of twisted nematic (TN)-liquid crystal displays (LCD) on polyimide (PI) surfaces. X-ray photoelectron spectroscopic analysis showed that the intensity of C=O chemical bonding decreased, while that of C-O chemical bonding increased for increasing IB incident angles. This indicates that the dipole-dipole interaction between C-O chemical bonding and the LC molecules has a chemical alignment effect. A good uniform alignment of nematic LCs on PI surfaces by the IB irradiation was observed, and good EO properties of IB-aligned TN-LCDs on PI surfaces were achieved. [ABSTRACT FROM AUTHOR]

We report on the fabrication of soluble pentacene-based thin-film transistors (TFTs) that consist of NiOx, poly-vinyl phenol (PVP), and Ni for the source-drain (S/D) electrodes, gate dielectric, and gate electrode, respectively. The NiOx S/D electrodes of which the work function is well matched to that of soluble pentacene are deposited on a soluble pentacene channel by sputter deposited of NiO target and show a moderately low but still effective transmittance of ∼ 65% in the visible range along with a good sheet resistance of ∼ 40 Ω/□. The maximum saturation current of our soluble pentacene-based TFT is about 15 µA at a gate bias of - 30 V showing a high field effect mobility of 0.03 cm2/Vs in the dark, and the on/off current ratio of our TFT is about 104. It is concluded that jointly adopting NiOx for the S/D electrodes and PVP for gate dielectric realizes a high-quality soluble pentacene-based TFT. [ABSTRACT FROM AUTHOR]

The process for depositing indume-tin oxide (ITO) electrode on polymer substrate is not readily applicable at high temperature and shows poor electrical properties than the conventional ITO deposition process on glass substrate. Especially, the deformation of polymer substrate and residual stress yield the crack which degrade the performance of organic light emitting diode (OLED) unit. In this study, we developed low resistance ITO electrode, AZO(ITO-ZnO-Ag-ZnO-ITO) to apply to the fabrication of the bottom emission OLED unit. The performance of the AZO exhibited low surface resistance as 8 ohm and the ITO electrodes were additionally deposited to guarantee the same work function as conventional ITO. The emissive efficiency was 92% at 550 nm which almost corresponds to that of the conventional ITO. [ABSTRACT FROM AUTHOR]

Applying inorganic thin film to liquid crystal (LC) alignment layer has been observed for the alternative of the LC alignment method. In this study, LC alignment characteristics of the nitrogen doped diamond like carbon (NDLC) thin film which was deposited using different deposition method-sputtering and plasma enhanced chemical vapor deposition (PECVD) system was investigated. The difference of the thin film deposition method and the rate of composition gas can affect the LC alignment. The NDLC thin film that was deposited using sputter showed uniform LC alignment at the 1200 eV of the ion beam intensity while the NDLC thin film that was deposited using PECVD showed uniform LC alignment at the 1800 eV of the ion beam intensity in our previous research. The uppermost of the thermal stability of NDLC thin film was 200°C. However, NDLC thin film deposited using sputter showed stability at high temperature, compared with NDLC thin film deposited using sputter. [ABSTRACT FROM AUTHOR]

In this study, liquid crystal (LC) alignment effects for homeotropic alignment on the SiOx thin film by electron beam evaporation method with electron beam system and electro-optical (EO) performances of homeotropic aligned liquid crystal display (LCD) were studied. Also, the control of pretilt angles of homeotropic aligned LC on SiOx thin film as a function of thin film thickness were investigated. The uniform vertical LC alignment on the SiOx thin film surfaces with electron beam evaporation was achieved in any of the thin film thickness conditions. It is considered that the LC alignment on the SiOx thin film by electron beam evaporation is attributed to the elastic interaction between LC molecules and micro-grooves at the SiOx thin film surface created by evaporation. In addition, LC cell of the SiOx thin film by electron beam evaporation had good EO property. [ABSTRACT FROM AUTHOR]

We recently achieved the homogeneous alignment of liquid crystal (LC) on amorphous Ta2O5 layers. This study demonstrates that LC layers could be aligned either homogeneously or vertically by increasing the growth temperature of rf magnetron sputtering device and the irradiation time of the DuoPIGatron type Ar ion beam device causing uniform and dense plasma. We attained two LC orientations by observing Ta 4f and O 1s peak shifts with x-ray photoelectron spectroscopy. Moreover, the decreased thickness of layers with high-k dielectric constants helped to decrease driving LC voltages and in turn to achieve low power consumption. [ABSTRACT FROM AUTHOR]