• Journal of the Korean Applied Science and Technology
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• v.20 no.2
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• pp.148-153
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• 2003

Electron transfer through an Langmuir-Blodgett(LB) monolayer film sandwiched between metal electrodes. We used an eicosanoic acid material and the material was very famous as a thin film insulating material. Eicosanoic acid monolayer was deposited by Langmuir-Blodgett(LB) technique and a subphase was a $CdCl_2$ solution as a 2${\times}10^{-4}$ mol/L. Also we used a bottom electrode as an Al/$Al_2O_3$ and a top electrode as a Al and Ti/Al. Here, the $Al_2O_3$ on the bottom electrode was deposited by thermal evaporation method. The $Al_2O_3$ layer was acted on a tunneling barrier and insulating layer in tunnel diode. It was found that the proper transfer surface pressure for film deposition was 25 mN/m and the limiting area per molecule was about 24 ${\AA}^2$/molecule. When the positive and negative bias applied to the molecular device, the behavior shows that a tunnel switching characteristics. This result were analyzed regarding various mechanisms.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.417-428
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• 2018

In this study, we fabricated hierarchically self-assembled thin films composed of graphene oxide (GO) sheets and gold nanoparticles (Au NPs) using the Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) techniques and investigated their gas-sensing performance. First, a thermally oxidized silicon wafer ($Si/SiO_2$) was hydrophobized by depositing the LB films of cadmium arachidate. Thin films of ligand-capped Au NPs and GO sheets of the appropriate size were then sequentially transferred onto the hydrophobic silicon wafer using the LB and the LS techniques, respectively. Several different films were prepared by varying the ligand type, film composition, and surface pressure of the spread monolayer at the air/water interface. Their structures were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their gas-sensing performance for $NH_3$ and $CO_2$ was assessed. The thin films of dodecanethiol-capped Au NPs and medium-sized GO sheets had a better hierarchical structure with higher uniformity and exhibited better gas-sensing performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.397-400
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• 1996

We investigated electric and dielectric properties of MIM device using Maleate Copolymer LB films. The thickness of maleate copolymer LB film by ellipsometry measurements and X-ray diffraction pattern was about 27~30[ ]. The maleate copolymer 13 film have the property of insulator like organic ultra-thin film. The electric conduction was Schottky current measured by I-V characteristics, and the conductivity was 10$^{-15}$ ~10$^{-14}$ [S/cm]. Dielectric constant was about 5.0~6.0 by various measurement: I-V, frequency-depenent dielectric properties. Schottky barrier was about 0.9 ~1.0(eV). By relation between log I and 1/T, activation energy baa 0.74(eV). Frequency-depenent dielectric properties wart orientational polarization by the dipole.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.258-260
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• 1996

We fabricated MIM device using copolymer LB films of $C_{18}MA-VE_2$. Electric and dielectric properties of MIM device were investigated. In our experimental results, the thickness of maleate copolymer LB film by elipsometry measurements was about $27{\sim}30[\AA]$. Conductivity was found to be $10^{+15}{\sim}10^{-14}[S/cm]$. The maleate copolymer LB film have the property of insulator like organic ultra-thin film. Frequency-dependent dielectric properties was orientational polarization by the dipole.

• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.55-62
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• 1998

The absorption spectra of polyamic acid containing p-methoxyazobenzene in a mixture of N, N-dimethylacetamide(DMAC) and benzene(1:1 by volume) solution was induced photoisomerization by UV and visible light irradiation. This solution is influenced on temperature according to measure by UV-Vis Spectrophotometer. Ultra thin film of polyamic acid containing p-methoxyazobenzene was prepared on the hydrophilic quartz plate by Langmuir-Blodgett(LB) method. The precursor LB film was heated in a vacuum dry oven at $120^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.57-60
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• 2001

The characterization of organic Metal/Insulator/Metal(MIM) devices were investigated from LB films. The physicochemical properties of the LB films were by UV absorption spectrum and AFM. We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 2, 10, 30[mN/ml The stable images are probably due to a strong interaction between the monolayer film and glass substrate. We are unable to obtain molecule resolution in images of the films but did see a marked contrast between images of the bare substrate and those with the network structure film deposited onto it.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.172-174
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• 1988

Studies and measurements of open circuit voltage in a metal/insulator/metal structure where metal are electrodes, when the insulator molecules have dipole moments all oriented parallel to each other have been reported here. The measured voltage has been shown to be directed related to the dipole moment of the molecules in the films. The insulator ultra thin films was deposited on them by the Langmuir-Blodgett technique to obtain the structure referred to as z type and Hetero structure of LB films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.822-825
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• 2003

Maxwell displacement current (MDC) measurement has been employed to study the dielectric property of Langmuir-films. A method for determining the dielectric relaxation time $\tau$ of floating monolayers on water surface is presented. WC flowing across monolayers is analyzed using a rod-like molecular model. It is revealed that the dielectric relaxation time $\tau$ of monolayers in the isotropic polar orientational phase is determined using a liner relationship between the monolayer compression speed ${\alpha}$ and the molecular area Am. Compression speed ${\alpha}$ was about 30, 40, 50mm/min.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1115-1121
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• 1998

MLS capacitor with lipid ultra thin films were deposited by Langmuir-Blodgett (LB) method on the silicon wafer. The current versus voltage and capacitance versus voltage relationships are depend on the applied voltage, electrode area and electrode materials. LB films deposited were made of L-$\alhpa$-DLPC, the 1 layer’s thickness of 35${\AA}$ was measured by ellipsometer. And MLS capacitor with different electrode materials, the work function of these materials was investigated to increase the leakage current. The result indicated the lower leakage current and very high saturation value of capacitance was reached within 700-800 pF when the two electrode was Ag. And $\varepsilon$1, $\varepsilon$2 versus photon energy showed good film formation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.143-146
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• 1999

In this study, Ultra-thin films of (N-ducosyl quinolinium)-TCNQ(1:2) complex were prepared on the hydrophilic substrate by Langmuir-Blodgett(LB) technique. By measure of UV-vis spectra and capacitance, deposition status was confirmed together with the thickness of natural oxidized aluminum film inside a device and dielectric constant of (N-docosyl quinolinium)-TCNQ(1:2) complex. The electrical properties of (N-docosyl 7uin7linium)-TCNQ(1:2) complex were investigated at room temperature. The conductivity of this film measured by the direction uf either vertical or horizontal axis is results in a quite different value.