• Journal of IKEEE
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• v.25 no.1
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• pp.64-68
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• 2021

We demonstrate an effect of annealing temperature on imprinting process of BiLaO thin film for liquid crystal alignment. BiLaO prepared sol-gel process was deposited by spin coating on a glass substrate, and then transferred to a pre-fabricated aligned pattern which is fabricated on a silicon wafer by laser interference lithography. Thin film was annealed at different temperature of 100, 150, 200, and 250 ℃. From the polarized optical microscopy analysis, the liquid crystal orientation was not uniform at the annealing temperature of 200 ℃ or lower and the uniform liquid crystal alignment characteristics were confirmed at the annealing temperature of 250 ℃. From atomic force microscopy, the pattern was not transferred at a temperature of 200 ℃ or lower. In contrast, the pattern was transferred at 250 ℃. Anisotropy of the thin film was obtained by the alignment pattern transferred at a temperature of 250 ℃, and the liquid crystal molecules could be evenly oriented on the thin film. Therefore, it was confirmed that the liquid crystal alignment process by the imprinting process of the BiLaO oxide film was affected by the annealing temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1133-1138
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• 1998

In this paper, we obtained the monodomain alignment of nematic liquid Crystal(NLC) in the cell fabricated by transcription alignment method on polyimide(PI) surface with side chain. It is considered that the LC alignment produced by the transcription alignment method is attributed to a memory effect of the NLC on PI surfaces. Also we observed that the generated pretilt angle of NLC is about $3.7^{\circ}$ with transcription alignment on PI surface. Next, we measured that the voltage-transmittance characteristics of transcription-aligned TN-LCD are almost same compared to rubbing-aligned TN-LCD. Also, we measured that the curve of transcription-aligned TN-LCD is less sharp than that of the rubbing-aligend TN-LCD in the decay time characteristics. It is considered that the response time characteristics of transcription-aligned TN-LCD are attributed to the weak anchoring strength between the LC molecules and the polymer surface.

• Electrical & Electronic Materials
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• v.10 no.9
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• pp.876-880
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• 1997

In this paper we investigated the transcription of liquid crystal (LC) alignment method by using memory effect of nematic(N) LCon polymide(PI) surface with side chain as for non-rubbing alignment techniques. That the monodomain alignment of aligned NLC is observed by microscope textures in the cells on PI surface with side chain. We obtained that the pretilt angle of NLC are generated about 3.7$^{\circ}$on PI surface. We suggest that the LC alignment by using transcription alingnment method is attributed to memory effect of NLC on PI surface.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.457-457
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• 2011

단일벽 탄소나노튜브(SWNTs)는 직경 및 키랄(chiral)특성에 따라 반도체성 튜브와 금속성 튜브로 구분되며, 작은 직경의 SWNTs는 큰 직경의 튜브에 비하여 일반적으로 기계적 특성이 뛰어나다고 알려져 있다. 따라서, 합성하는 단계에서 SWNTs의 직경 및 chiral 특성의 제어가 가능 하게 된다면 전자소자로의 응용을 한층 앞당길 수 있을 것으로 예상하고 있다. 이와 더불어 SWNTs의 수평배향성장은 SWNTs의 집적(integration)을 용이하게 할 수 있기 때문에 향후 나노전자소자 개발을 목표로 최근 많은 연구결과들이 보고되고 있다. 하지만 현재는 SWNTs가 고밀도로 합성되기 때문에, 우수한 개별 (individual) SWNT의 전기적 특성보다는 집단적(ensemble) 특성을 얻고 있다. 따라서, 합성기판 위에서 개별적인 SWNT를 낮은 밀도로 수평배향 성장하는 일은 향후 나노튜브기반의 고성능 전자소자 개발에 중요한 과제이다. 나아가, 수평배향 성장 된 개별 SWNT의 직경 및 키랄 특성까지 함께 제어할 수 있다면 곧바로 응용에 적용할 수 있는 획기적인 기술이 될 것이다. 본 연구에서는, SWNTs의 수평배향도 및 직경을 제어하여 성장시키는 것을 목표로 하였다. 합성기판은 퀄츠를 이용하였고, 합성촉매로는 나노입자의 밀도를 비교적 쉽게 제어할 수 있고, 균일한 크기를 갖는 페리틴 단백질을 이용하였다. 단분산(monodispersion) 된 촉매 나노입자를 얻기 위해서 스핀코팅 조건과 페리틴 용액농도를 조절하여 퀄츠기판 위에 분산시킨 후, 아르곤 분위기 하에 열처리를 통하여 촉매 나노입자의 크기 감소를 유도하였다. 그 결과 열처리 시간이 증가함에 따라 촉매 나노입자의 크기가 감소하는 것을 알 수 있었고, SWNTs의 직경 또한 감소하는 것을 확인하였다. 또한 퀄츠기판 위에 직경제어 합성 된 수평배향 SWNTs를 다른 기판으로 전사하는 기술을 확립함으로써, 향후 SWNTs기반의 소자 제작기술의 바탕을 마련하였다.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1812-1814
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• 1999

The effects of polarity of the polymer on transcription-aligned twisted nematic (TN)-liquid crystal display (LCD) on various the polyimide (PI) surfaces were investigated. The monodomain alignment of nematic (N)LC is obtained in cells fabricated by transcription alignment method on PI surface with medium polarity. The LC alignment using transcription alignment method is attributed to polarity of the polymer. The threshold voltage of transcription-aligned TN-LCD decreases with increasing the polarity of the polymer on three kinds of the PI surfaces. The threshold voltage of transcription-aligned TN-LCD on PI surface with high polarity is almost the same compared to rubbing-aligned TN-LCD. The response time of transcription-aligned TN-LCD decreases with the increasing the polarity of the polymer on all PI surfaces. The decay time of transcription-aligned TN-LCD is slow compared with the rubbing-aligned TN-LCD.

• Journal of IKEEE
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• v.23 no.2
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• pp.594-598
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• 2019

We demonstrate an alternative alignment process using transferring process on solution driven HfZnO film. Parallel pattern is firstly fabricated on a silicon wafer by laser interference lithography. Prepared HfZnO solution fabricated by sol-gel process is spin-coated on a glass substrate. The silicon wafer with parallel pattern is placed on the HfZnO film and annealed at $100^{\circ}C$ for 30 min. After transferring process, parallel grooves on the HfZnO film is obtained which is confirmed by atomic force microscopy and scanning electron microscopy. Uniform liquid crystal alignment is achieved which is attributed to an anisotropic characteristic of HfZnO film by parallel grooves. The liquid crystal cell exhibited a pretilt angle of $0.25^{\circ}$ which showed a homogeneous alignment property.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1388-1390
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• 1998

In this paper, we investigated the monodomain alignment of nematic liquid crystal(NLC) in the cell fabricated by transcription alignment method on polyimide(PI) surface with side chain. The LC alignment produced by the transcription alignment method is attributed to a memory effect of the NLC on PI surfaces. We observed that the pretilt angle of NLC is generated about $3.7^{\circ}$ with transcription alignment on PI surface. Also, we obtained the good electro-optical(EO) performance of twisted nematic(TN)-liquid crystal display(LCD) by transcription alignment method on PI surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.271-274
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• 1998

In this paper, the monodomain alignment of nematic liquid crystal(NLC) in the cell fabricated by one side transcription alignment method on PI surface with side chain were investigated. The LC alignment produced by the transcription alignment method is attributable to a memory effect of the NLC on Pl surfaces. We observed that the pretilt angle of NLC is generated about 3.6$^{\circ}$ in a cell with one side transcription alignment on PI surface. Also, the electro-optical(EO) performance of TN-LCD with one side transcription alignment method on PI surface will be discussed.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1582-1584
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• 1997

We investigated the transcription of liquid crystal (LC) alignment method by using memory effect of nematic (N) LC on polyimide (PI) surface with side chain as for non-rubbing alignment techniques. That the monodomain alignment of aligned NLC is observed by polarizing microscope textures in the cells on PI surface with side chain, We obtained that the pretilt angle of NLC are generated about 3.7 degree on PI surface. We suggest that the LC alignment by using transcription aligngnment method is attributed to memory effect of NLC on PI surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.123-126
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• 1997

In this study, we investigated the Pretilt ang1e generation in nematic liquid crystal (NLC) by using the transcription, alignment on polyimide(Pl) surfaces. That the uniform alignment of NLC is observed by microphotograph textures in LC cells on Pl surface. We obtained that the pretilt angle of NLC are generated about 3.6$^{\circ}$on Pl surface. It is considered that the LC alignment by transcription alignment method is attributed to memory effect of LC on Pl surface.