• 한국전기전자재료학회논문지
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• 제14권9호
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• pp.757-761
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• 2001

We studied emitting properties of organic electroluminescent devices fabricated using the spin-coating and Langmuir-Blodgett(LB) technique. The LB technique has the advantage of precise control of the thickness better than spin-coating method. LB monolayer of poly(3-hexylthiophene)(P3HT) was deposited 27 layers onto the indium-tin-oxide(ITO) substrate as Y-type films by the vertical dipping method. In the absorption spectra, the λ$\_$max/ of P3HT-AA LB films and of spin-coating films showed about at 510, 545 and 590 nm corresponding to 2.43, 2.28, 2.10eV. And we observed that the turn-on voltage of devices deposited by LB method(10V) was higher than that of spin-coating method(8.5V) in voltage-current-luminance characteristic. In the logV-logJ characteristics of ITO/P3HT-AA LB/Al device, we confirmed that El device fabricated by LB method follows three conduction mechanisms: ohmic, space-charge-limited current(SCLC) conduction and trapped-carrier-limited space-charge current(TCLC) conduction.

• 대한전기학회논문지
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• 제44권10호
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• pp.1311-1316
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• 1995

The electrical properties of the Langmuir-Blodgett (LB) films layered with arachidic acid were studied at the room temperature. The sample was formed with 2 different structure ; One was Al/LB/Al and the other was Au/LB/Au. The precise structure of Al/LB/Al was considered as Al/Al$_{2}$O$_{3}$/LB/Al, because the natural oxide layer was formed on surface of lower Al electrode. The electrical conductivity of Al/Al$_{2}$O$_{3}$/LB/Al structure was determined the value of 3.5 * 10$^{-14}$ S/cm from the measurement of current-voltage (I-V) characteristics. The sample with the structure of Au/LB/Au was made to eliminate the influence of oxide layer in the electrical properties of the LB films. The short circuit current was observed in this sample from the I-V characteristics. To verify the reason of short circuit current generation, copper decoration method was employed to the 15 layers of LB films deposited on the Al and Au electrode each. The defects were shown on the films deposited with Au electrode. This results means that the defects on the LB films which layered with the Au electrode were contributed to the short circuit current. Several films (15, 31, 51, 71L) were deposited on the Au electrode and measured the size of defects with the copper decoration method. The size of defects becomes smaller as the film layer was increased. We conclude that the existence of defects affects the short circuit current generation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.962-964
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• 1999

We studied emitting properties of devices fabricated using the spin-coating and Langmuir-Blodgett[LB] technique. The LB technique has the advantage of precise control of the thickness better than spin-coating method. Poly(3-hexylthiophene)[P3HT] LB films used as the emitting layer in light-emitting devices. LB monolayers were deposited 27 layers onto the indium-tin-oxide[ITO] as Y-type films by the vertical dipping method. The thickness is about 80nm. Absorption spectrum of LB films presented that P3HT is regiorandom conformation. Also, current-voltage-luminance characteristics and electroluminescence spectra of light-emitting devices fabricated by LB method is studied. In current-voltage-luminescence characteristics, turn-on voltage of P3HT LB film LEDs is higher than that of spin-coating LEDs. But electroluminescence spectrum is similar to the spin-coating LEDs. The orange-red light was clearly visible in a darkened room.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권5호
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• pp.379-384
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• 1999

Langmuir-Blodgett(LB) films which have high ordered orientation and ordering structure are fabricated by LB method which deposit the ultra-thin films of organic materials at a molecular level. The electrical characteristics of stearic acid LB ultra-thin films for the horizontal direction were investigated to develop the gas sensor using LB ultra-thin films. The optimal deposition condition to deposit the LB ultra-thin films was obtained from $\pi-A$ isotherms and the deposition status of stearic acid LB ultra-thin films was verified by the measurement of deposition ratio, UV-absorbance, and electrical properties for LB ultra-thin films. The conductivity of stearic acid LB ultra-thin films for horizontal direction was about $10_{-8}[S/cm]$. The activation energy for LB ultra-thin films with respect to variation of temperature was about 1.0[eV], which was correspond to semiconductor material. The response characteristics for organic gas were confirmed by measuring the response time, recovery time, and reproducibility of the LB ultra-thin to each organic gas. Also, the penetration and adsorption behavior of gas molecule were confirmed through the organic gas response characteristics of LB ultra-thin films with respect to temperature.

• 대한기계학회논문집B
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• 제37권7호
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• pp.683-693
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• 2013

본 연구에서는 혼성 격자볼츠만 방법(HLBM)을 이용하여 상판이 일정한 속도로 움직이는 공동 형상 내부에서의 혼합 특성에 대하여 수치적으로 연구하였다. 먼저, 공동 형상에서 기존의 신뢰성 있는 유동장 결과와의 비교를 통해 LB-SRT 모델과 LB-MRT 모델의 신뢰성을 검토하였다. 두 모델 모두 기존의 연구결과와 유사한 결과를 보였으나, LB-MRT 모델이 LB-SRT 모델보다 높은 Re수에서는 수치적 안정성이 높은 것을 확인하였다. 수치적 안정성이 좋은 LB-MRT 모델을 토대로 유한차분법을 적용한 HLBM을 이용하여 공동 형상 내부에서의 농도장을 수치 해석하였다. Re수와 Pe수를 변화하여 공동 형상 내부의 혼합 특성과 물질 전달 형태에 대하여 파악하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 센서 박막재료
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• pp.11-14
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• 2001

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 30[mN/m]. LB layers of Arac. acid deposited by LB method were deposited onto slide glass as Y-type film. The physicochemical properties of the LB films were examined by UV absorption spectrum, SEM and AFM. The structure of manufactured device is Au/arachidic acid/Al. the number of accumulated layers are 3~9. Also. we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from -3 to +3[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.146-149
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• 1999

Langmur-Blodgett (LB) method has a unique characteristic of making molecularly mutilayered aggregation structures. LB method makes the thickness of organic insulation layer controllable at molecular scale in various electronic devices. In this study, the organic materials applicable to crosslinked LB insulation layers of electronic devices have developed and the electrical properties of their LB films have examined such as Brewster angle microscopy(BAM), Scanning Maxwell-stress microscopy(SMM), and Current-voltage(1-V) properties.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권7호
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• pp.508-513
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• 1999

The response properties of quartz crystal coated with stearic acid LB films to organic gases were investigated by measuring the shift of resonant frequency. Stearic acid was used as a sensing material and deposited on the surface of quartz crystal using the Langmuir-Blodgett(LB) method. The effect of temperature on the quartz crystal coated with stearic acid LB films was also investigated by Scanning Maxwell-stress Microscopy(SMM). As a result, the sensitivity of the quartz crystal coated with LB films to organic gases is dependent on temperature, thickness of LB film and molecular weight of organic gas.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.628-636
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• 1998

LB layers L-$\alpha$-DLPC deposited by LB method were deposited onto n-type silicon wafer as Z-type film. Films made up of 8, 16 layers of lipid with long alkyl chain and the thickness of monolayer and multiayers was determined by ellipsometry. Ut was deposited Ag and Al onto LB layers and silicon wafer for electrode and small electrode exhibit high capacitiance and low lekage current. The C-V curves of the MLS capacitor shows very high saturation value of capacitance. And cross-sectional SEM image of MLD capacitor indicated the presence of pore with Al electrode and we found that the Ag is good for electrode metal.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.347-349
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• 1999

We have fabricated insulating thin films using p-hexadecoxyphenol(p-Hp) that was formed phenol-formaldehyde resin of crosslinked structure from reaction with formaldehyde by LB technique. For fabricated MIM device, the possibility for insulating layers of electronic were investigated by electrical properties of their LB films according to crosslinking of LB films current-voltage (I-V) properties and frequency-capacitance (C-F) characteristics. We have provided evidence for the high insulating performance of phenol-formaldehyde thin films by the LB method. Conductivity of their LB films was as follows: pure water > 1 % aq. Formaldehyde > heat treatment, in the current-voltage (I-V) characteristics. It is demonstrated that insulation properties of crosslinked p-HP LB films were improved. In capacitance-frequency properties, the heat-treated p-HP LB films for crosslinking showed a low relative dielectric constant.