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Surface smoothing of indium tin oxide (ITO) film by laser irradiation was demonstrated. The ITO surface was etched by choline radicals, which were activated by laser irradiation at a wavelength of 532 nm. The RMS surface roughness was improved from 5.6 to 4.6 nm after 10 min of laser irradiation. We also showed the changes in the surface morphology of the ITO film with various irradiation powers and times.

The surface of poly(methyl methacrylate) (PMMA) film was etched by laser irradiation under O2 and vacuum conditions. By activating the O2 molecules near the rough surface, oxygen radicals will preferably etch the protrusions on the PMMA surface. Three lasers of different wavelengths were used for comparison. Laser irradiation at a short wavelength such as 325 nm resulted in high etch rates whereas a long wavelength such as 532 nm resulted in no effect on the surface profile. The PMMA surface was not etched under the vacuum condition, indicating the necessity of O2 molecules in etching.

It is essential to align masks without tolerance in every deposition step when fabricating thin-film transistors (TFTs) on a polymer substrate. However, the shrinkage of the polymer substrate due to thermal effect may arise during the deposition process. We observed the variation of shrinkage as a function of the annealing temperature. It was found that the substrates keep shrinking up to a critical temperature and stay the same above that point. The thermal treatment was conducted on substrates polycarbonate (PC), the polyarylate (PAR), and poly(ether sulfone) (PES). After predeposition annealing, the shrinkage was prevented but deformation was observed on the surface. An inorganic thin film with a different thermal expansion coefficient was employed to remove the deformation and this resulted in the elimination of strain.

Nematic liquid crystal (NLC) alignment effects on SiNx thin film layers treated by ion-beam irradiation for three types of N ratio were successfully studied for the first time. The SiNx thin film was deposited by plasma-enhanced chemical vapor deposition using three types of N ratio. To characterize the film, atomic force microscopy was performed. Good LC aligning capabilities on the SiNx thin film treated by ion-beam irradiation for all N ratios can be achieved. The low pretilt angle for an NLC on the SiNx thin film treated by ion-beam irradiation was observed and could be adopted in planar alignment liquid crystal display applications as in-plane switching and fringe-field switching modes.

We have studied the liquid crystal (LC) alignment and tilt angle generation of a nematic liquid crystal (NLC) on a homeotropic polyimide (PI) surface using a new ion beam source. The tilt angle of the NLC on the homeotropic PI surface for all incident angles is about 38° and this angle has a stabilization trend. A good LC alignment of the NLC on the homeotropic PI surface by to exposure ion beam of 45° incidence angle was observed. Also, the tilt angle of the NLC on the homeotropic PI surface by to exposure ion beam of 45° incidence angle had a tendency to decrease as ion beam energy density increased. Thus, we demonstrated that the tilt angle could be controlled from vertical to horizontal directions. Also, the alignment character of the NLC on the homeotropic PI surface with respect to ion beam energy was good at more than 1500 eV. Finally, a superior LC alignment thermal stability on the homeotropic PI surface subject to ion beam exposure was achieved.

Dense and uniformly distributed arrays of holes and nanodots were fabricated in silicon oxide and silicon. The holes were approximately 25 nm wide, 40 nm deep, and 60 nm apart. To obtain nano size patterns, self-assembling resists were used to produce a layer of uniformly distributed parallel cylinders of poly(methyl methacrylate) (PMMA) in a polystyrene (PS) matrix. The PMMA cylinders were degraded and removed by acetic acid rinsing to produce a PS mask for pattern transfer. The silicon oxide was removed by fluorine-based reactive ion etching (RIE). Selectively deposited tungsten nanodots were formed inside nano sized trenches by low pressure chemical vapor deposition (LPCVD). The tungsten nanodots and silicon trenches were 26 and 30 nm, respectively.

We investigated the liquid crystal (LC) aligning capabilities and electrooptical characteristics of transparent Al-doped ZnO (ZnO:Al) electrodes substituting indium tin oxide (ITO) electrodes. Experimental results show that a uniform vertical LC alignment and a large pretilt angle were achieved using the ZnO:Al electrodes. The vertical alignment mode based on the ZnO:Al electrodes showed appropriate electrooptical characteristics and a high transparency in comparison with that based on the ITO electrodes. These results indicate that the transparent ZnO:Al electrodes of liquid crystal displays could substitute the ITO electrodes.

We studied liquid crystal (LC) aligning capabilities on a treated SiOx thin-film surface by 45° evaporation with an electron beam system. A uniform vertical LC alignment on SiOx thin-film surfaces was achieved. A high pretilt angle of about 86.5° was obtained. A good LC alignment on treated SiOx thin-film layers by 45° evaporation with electron beam was also observed at an annealing temperature of 250 °C. The high pretilt angle and the good thermal stability of LC alignment on SiOx thin-films by 45° obliqued electron beam evaporation can be achieved.

Noble quantum wire structures were grown by low-pressure metalorganic chemical vapor deposition (MOCVD). Triangular InGaAs/GaAs quantum wire structures with sharp tips and smooth sidewalls were grown on SiO2 masked GaAs substrates. To characterize and analyze the selectively grown structures, scanning electron microscopy and temperature-dependent photoluminescence were used. Even though the opening width was different, it was possible to obtain a similar triangular structure. If we use this quantum confined structure of different size, it would be possible to grow quantum wire structures with various thicknesses and fabricate uniquely integrated optical devices which include light-emitting sources of multiple wavelength. The emission peak from quantum wires was observed at 975 nm. With increasing temperature, the emission intensity from side wall quantum wells decreased abruptly. However, the intensity from quantum wires decreased slowly compared to that from side wall quantum wells and it became even stronger above 50 K. The possible carrier capture processes in the quantum wire structures were also discussed.

We achieved vertically aligned (VA) liquid crystals (LCs) on amorphous tantalum pentoxide (Ta2O5) alignment films deposited by radio frequency (rf) magnetron sputtering using ion beam (IB) irradiation. By analyzing measurements by X-ray photoelectron spectroscopy (XPS), we confirmed the bond breaking, as detected from the O 1s spectra, which caused an isotropic dipole–dipole interaction between the LC molecules and the Ta2O5 alignment film to uniformly align the vertical LC molecular orientation as a function of IB energy density. Moreover, by examining the electro-optical (EO) characteristics of the Ta2O5 surfaces compared with those of the polyimide (PI) alignment layer, we confirmed that Ta2O5 has a low threshold voltage and a low power consumption when used as an LC alignment layer.

In this paper, we describe the formation of vertically aligned liquid crystal molecules on TiO2 films treated by ion-beam (IB) irradiation. Regular or irregular pretilt angles were achieved as a function of IB incident angle. Uniform alignment was obtained only at an incident angle of 45°. The contact angle, which is related to the surface energy, was measured to confirm the tendency of variation in the pretilt angle. In addition, the weak anchoring energy of LC molecules on IB-irradiated TiO2 was ascertained by the thermal stability at low temperature.

We demonstrated the annealing effects displayed by liquid crystal antiparallel cells made from ion beam-irradiated blended polyimide layers. The pretilt angles of the liquid crystals after annealing at 90 °C for 10 min were similar to those before annealing, which demonstrates good thermal stability for liquid crystal antiparallel cells. Contact angle increases as vertical polyimide concentration increases, a trend that corresponds closely to the variation in pretilt angle. Uniform liquid crystal alignment was observed from a photomicrograph. Strong anchoring energies allowed the liquid crystal to maintain homeostasis and withstand thermal stress.

The dipole–dipole interaction between liquid crystals (LCs) and a polystyrene (PS) surface induced by ion beam (IB) irradiation was successfully studied. The LC molecular orientation follows the IB alignment direction on the PS surface, upon IB irradiation or rubbing. The LC orientation on the PS surface is fixed by IB irradiation and is not affected by rubbing. Also, the LC alignment direction depends strongly on the C=O bonds formed from the C=C and C–C bonds on the PS surface that are broken by the IB irradiation. The LC alignment induced by IB irradiation on the PS surface using dipole–dipole interaction between the LCs and the PS surface is more strongly affected by the chemical bonding of broken chains than by physical processes such as the microgroove effect and π–π interaction. Furthermore, the anchoring strength of LCs on the PS surface upon IB irradiation is stronger than that of the PS surface upon rubbing as indicated by the LC orientation direction.

We examined the transition behavior of the tilt angle on homeotropic polyimide (PI) surfaces as a function of ion beam (IB) irradiation incident angle. We also investigated the liquid crystal (LC) orientation mechanism by X-ray photoelectron spectroscopy. The tilt angles of the IB-irradiated PI surfaces were controlled in the range of 82–90° as functions of IB irradiation time and incident angle. The largest deviation from the homeotropic alignment was achieved at an IB incident angle of 45°. The plot of the atomic percentage of C–O binding energy versus IB incident angle was shaped like an upward-pointing triangle, while that of the C=O binding energy versus IB incident angle was the reverse. The tilt angle behavior as a function of IB incident angle was similar to the atomic percentage behavior. The LC alignment with IB irradiation was due to the dipole–dipole interaction between the C–O single bonds and the LC molecules. An excellent voltage–transmittance curve for the vertical alignment (VA)-LC cells was observed with a threshold voltage behavior related to the tilt angle. Suitable response time characteristics were measured for VA-LC cells treated with IB irradiation.

We report 90° domains in (110)-oriented polycrystalline BaTiO3 thin films. The domain and crystal structures of the thin films were investigated using transmission electron microscopy and high temperature X-ray diffraction, respectively. From X-ray diffraction, it was found that the prepared films had a (110)-preferred orientation and a tetragonal structure at room temperature. Observation in the plan-view and cross-sectional modes using transmission electron microscopy clearly indicated the presence of a 90° domain structure. In the cross-sectional mode, a 90° domain structure was observed along the film growth direction and in the plan-view mode, it was also found that a 90° domain boundary was initiated from the (111) twin boundary. The formation of a 90° domain boundary was discussed in terms of planar defects such as the (111) twin and we also proposed two kinds of stress relief mechanisms induced by 90° domain formation.

Polycrystalline BaTiO3 thin films were prepared by rf magnetron sputtering and twin structures in the thin films were investigated using a transmission electron microscope. (111) twin boundaries were found in the thin films with thicknesses of 2100 and 10000 Å. Not only single twin boundaries but (111) twin lamellae with a very narrow width of ≈1 nm were observed in thin films of both thicknesses. This result suggested that the twin lamellae would be stable although the interfacial energy appeared to be much higher than single twin boundaries. A correlation between twin lamella width and grain size was also found.