• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.395-400
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• 2014

We proposed a method for fast turn-off switching of a vertically-aligned liquid crystal cell by low-temperature curing of the polymer structure. We confirmed that the turn-off times of the fabricated cells were reduced significantly as the curing temperature was lowered to $-20^{\circ}C$. We accounted for the effect of low-temperature curing on the turn-off time by using a mathematical model and by observing images obtained via scanning electron microscopy. We also confirmed that low-temperature curing is more effective in reducing the response time when the device is operated at a low temperature.

• Journal of Sensor Science and Technology
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• v.27 no.4
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• pp.264-268
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• 2018

Vertically-aligned $TiO_2$ nanotube electrodes have attracted considerable attention for applications in solar cells, catalysts, and sensors, because of their ideal structure for electron transport and electrolyte diffusion. Here, we prepare vertically-aligned $TiO_2$ nanotube electrodes using a two-step anodization process. The prepared $TiO_2$ nanotube electrodes exhibit uniform pore structures with an inner diameter of ~80-90 nm and wall thickness of ~20-25 nm. In addition, they exhibit an anatase crystal phase after a high-temperature annealing. The annealed $TiO_2$ nanotube electrodes are applied in dye-sensitized solar cells (DSSCs) as photoanodes. The fabricated DSSC exhibits conversion efficiencies of 3.46 and 2.15% with liquid- and gel-type electrolytes, respectively.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.67.2-67.2
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• 2018

Magnetic fields play an important role in star-forming processes by regulating gravitational collapse. In filamentary structures of star-forming regions, magnetic fields are likely to be aligned with minor axes of filamentary molecular clouds because matter freely moves along magnetic field lines. Orion A region, one of the well-known high-mass star forming regions, has long filament structure. In order to study magnetic field directions with respect to the filamentary structure in Orion A, we have analyzed $850{\mu}m$ dust polarization observations obtained with the James Clerk Maxwell Telescope (JCMT). We found tight correlation of dust intensity gradients and magnetic field directions. It was estimated that 81% of magnetic field segments are aligned with density gradients within 40 degree. In conclusion, we confirmed most of magnetic field segments are perpendicular to the major axis of the filament in Orion A.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.303-306
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• 2005

We report the self-aligned low temperature poly silicon (LTPS) TFT process using simple doping process. In conventional LTPS-TFT, the Lightly Doped Drain (LDD) doping and source/drain doping are processed separately by aligning the gate with the source and drain during the gate lithography step. This ne w process not only fabricates fully self-aligned low temperature poly silicon TFTs with symmetric LDD structure but also simplifies the process flow with combined source/drain doping and LDD doping in one step. LDD doping process can be achieved using only source/drain doping process according to the new structure. In this paper, the TFT characteristics of NMOS and PMOS using the new doping process will be discussed.

• Journal of Electrical Engineering and information Science
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• v.2 no.4
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• pp.106-110
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• 1997

A new SOI NMOSFET with a 'LOCOS-like' shape self-aligned polysilicon gate formed on the recessed channel region has been fabricated by a mix-and-match technology. For the first time, a new scheme for implementing self-alignment in both source/drain and gate structure in recessed channel device fabrication was tried. Symmetric source/drain doping profile was obtained and highly symmetric electrical characteristics were observed. Drain current measured from 0.3${\mu}{\textrm}{m}$ SOI devices with V\ulcorner of 0.77V and Tox=7.6nm is 360$mutextrm{A}$/${\mu}{\textrm}{m}$ at V\ulcorner\ulcorner=3.5V and V\ulcorner=2.5V. Improved breakdown characteristics were obtained and the BV\ulcorner\ulcorner\ulcorner(the drain voltage for 1 nA/${\mu}{\textrm}{m}$ of I\ulcorner at V=\ulcorner\ulcorner=0V) of the device with L\ulcorner\ulcorner=0.3${\mu}{\textrm}{m}$ under the floating body condition was as high as 3.7 V. Problems for the new scheme are also addressed and more advanced device structure based on the proposed scheme is proposed to solve the problems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.1023-1028
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• 2003

The field emission characteristics are studied by simulation for carbon nanotube triode structures with a strip-shaped emitter and a gate hole aligned with it. Two structures, one with double-edge and the other with single edge are analyzed. They show good emission characteristics. Emissions of electrons are concentrated on the edges of emitter and the emitted current increases as the distance between emitter and gate decreases. For single-edged emitter, the emitted electrons form a narow strip-shaped beam which has a good directionality. These triode structures have advantages in that they can be easily fabricated and aligned for assembly.

• Applied Science and Convergence Technology
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• v.23 no.6
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• pp.351-356
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• 2014

The electronic structure at organic-organic interface gives essential information on device performance such as charge transport and mobility. Especially, the molecular orientation of organic material can affect the electronic structure at interface and ultimately the device performance in organic photovoltaics. The molecular orientation is examined by the change in ionization potential (IP) for metal phthalocyanines (MPc, M=Zn, Cu)/fullerene ($C_{60}$) interfaces on ITO by adding the CuI templating layer through ultraviolet photoelectron spectroscopy measurement. On CuPc/$C_{60}$ bilayer, the addition of CuI templating layer represents the noticeable change in IP, while it hardly affects the electronic structure of ZnPc/$C_{60}$ bilayer. The CuPc molecules on CuI represent relatively lying down orientation with intermolecular ${\pi}-{\pi}$ overlap being aligned in vertical direction. Consequently, in organic photovoltaics consisting of CuPc and $C_{60}$ as donor and acceptor, respectively, the carrier transport along the direction is enhanced by the insertion of CuI templaing layer. In addition, optical absorption in CuPc molecules is increased due to aligned transition matrix elements. Overall the lying down orientation of CuPc on CuI will improve photovoltaic efficiency.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.84.1-84
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.10a
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• pp.128-128
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• 1997

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1028-1029
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• 2006

We have developed a self-aligned single isolation structure (SIS) and an asymmetric single isolation structure with an image reversal photoresist to increase the aperture ratio in a passive matrix organic light emitting display (PMOLED). Compared to the conventional structure, the fabrication process is reduced by about 17% and the aperture ratio is enlarged over 4%.