• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.5-8
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• 1997

A study on the electrical conduction characteristics of the ultrathin organic films is one of the important factors for the development of molecular electronic devices. The Langmuir- Blodgett(LB) technique has recently been attracted interest as a method of the deposition ultrathin films. We hate fabricated N-docosyl N\`-methyl viologen-diTCNQ(DMVT) anion radical LB film and investigated the molecular orientation and electrical conduction characteristics. We have measured infrared transmission-reflection spectra. The alkyl chain is found to he well-ordered with the tilt angle of 13$^{\circ}$ with respect to the substrate surface normal and the TCNQ plane is tilted at 76$^{\circ}$ the surface normal. In ESR spectrum, we confirmed that a half-amplitude linewidth is clearly dependent on the incident angle, which indicates conducting species change. The in-plane conductivity of 31 lagers is approximately 1.33$\times$10$^{-6}$ S/cm. The ohmic behaviour was observed below 0.6 V, when current-voltage(I-V) characteristics was measured verically.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1200-1202
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• 1993

There are many methods to investigate the physical properties of monolayers formed at the air-water interface. Among them, the displacement current method is appropriate for the investigation of the dynamic behavior of monolayers. The measuring system of displacement current method was constructed at home-made Kuhn type LB deposition apparatus using aluminium plate electrode. The currents induced by the dynamic motion of molecules were measured when the molecules were pressed by barrier. To verify the measuring system, we used 4-octyl -4'-(5-carboxy-pentamethyleneoxy)-azobenzene molecules which has two remarkable variations of surface pressure of monolayer at the air-water interface. We can detect the two peaks of displacement currents which shows that the orientations of molecules are changed greatly at the state of these two remarkable changes of surface pressure.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1193-1196
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• 1993

Electrical properties of $C_{22}$-Quinolium(TCNQ) Langmuir-Blodgett(LB) films are reported depending on a type of applied voltage on a type of applied voltage and temperature. A conductivity was identified to be anisotropic with a ratio of ${\sigma}||/{\sigma}{\bot}{\simeq}10^7$ at room temperature. The I-V characteristics along the film surface direction show an ohmic behavior up to a few hundred volts. But the I-V characteristics in the vertical direction display an ohmic behavior for low-electric field, and a nonohmic behavior for high-electric field. This nonohmic behavior has already been interpreted as a conduction mechanism of space-charge limited current and Schottky effect near the electric-field strengh of $10^6$ V/cm. When the electric field exceeds further, there is anormalous phenomia similiar to breakdown. From the study of I-V characteristics with the application of step or pulse voltage, we have found that the breakdown voltage shifts to higher one as the step or pulse interval becomes shorter. These results indicate that the breakdown is due to both electrical and thermal effect. To see the infulence of temperature, current was measured as function of temperature with several bias voltages, which are lower than that of breakdown. It shows that the current increases about 3 orders of magnitude near $60{\sim}70^{circ}C$, and remains constant for a while up to $140^{\circ}C$ and then suddenly drops. Arahidic acid was used to cmpare with $C_{22}$-Quinolium(TCNQ) LB films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.343-346
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• 1999

We have investigated the dielectric and electrical characteristics of palrnitic acid(PA), stearic acid(SA) and arachidic acid(AA) Langmuir-Blodgett(LB) films because these fatty acid systems have a same hydrophilic group and a different hydrophobic one(alky1 chain lqngth). The dielectric characteristics such as the capacitance-frequency(C-F) characteristics and the dielectric dispersion and absorption characteristics of PA, SA and AA through-plane were measured. In the result, the relative dielectric constants of PA, SA and AA LB films were about 3.0-4.6, 2.7-4.1 and 2.4-3.8, respectively. The relative dielectric constants were decreased in proportion to the chain length of alkyl group. Also, the dielectric dispersion and absorption of each fatty acid LB films have arisen from the dipole polarization in the range of $10^4~10^5[Hz]. And, the conductivity of PA, SA and AA LB films obtained from I-V characteristics were about $9{\times}10^{-14}, 3{\times}10^{-l4} and 5{\times}10^{-15}[S/cm], respectively. These results have shown the insulating materials and could control the conductivity by changing the length of alkyl group. Also, we have confirmed that the barrier height of fatty acid systems were about 1.32-1.40[eV] and the dielectric constant were about 3.0-4.2. These values were almost the same ones obtained from dielectric characteristics.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.823-826
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• 2001

In the initial process of photosynthesis, a biological electron transfer system, photoelectric conversion occurs and then long-range electron transfer takes place very efficiently in one direction through the biomolecules. The metal/insulator/metal structured device consisting of GFP, viologen, cytochrome c hetero-thin film was presented based on the biomimesis. GFP, viologen, and cytochrome c was used as an electron sensitizer, a mediator, and an electron acceptor. Cytochrome c molecules and viologen molecules were deposited by Langmuir-Blodgett (LB) technique, and GFP molecules were adsorbed by self-assembly method (SAM). Surface morphology of hetero-thin film was analyzed by scanning tunneling microscopy (STM). Local photoswitching effects of a proposed photodiode were verified by current-voltage measurements using hybrid STM/I-V measurement system.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.175-178
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• 1988

A film is fabricated by depositing several sliced organic ultra thin films on a slide glass. Both UV-absorbance and the capacitance of a multi - layered organic ultra thin film with (N-docosyl pyridinium)-TCNQ(1:2) complex have a desired value on the condition of well alignment in depositing several layers. Forethermore the conductivity of this film measured by the direction of either horizontal or vertical axis. respectively, is results in a quite different value.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.362-365
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• 2002

This paper, experiment manufactures device of Metal/Poly-${\gamma}$ Benzyl $_D$-GlutamateOrganic Films/Metal structure using PBDG and I-V properties and C-F properties. The I-V characteristic is measured that approve voltage from 0 to +2[V] of device and the distance between electrode is larger, could know that small current flow and thin film could know that had insulation property. C-F characteristic has each other affinity between the polarization amount and frequency. Permittivity of MIM device could know by dipole that is voluntary polarization of LB film that polarization is happened. The capacitor properties of a thin film is better as the distance between electrodes is smaller.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.230-233
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• 1995

Using Polyimide Langmuir-Blodgett(LB) films as a tunneling barrier, Current -Voltage(I-V) characteristics and inelastic electron tunneling spectroscoupy(IETS) of the junctions incorporating 1-layer orgainc monolayer were invesgated. Several peaks originating in vibrational modes of constituted molecules of 1-layer monolayers were clearly observed in the IET spectra.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.228-231
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• 1995

Phthalocyanine have a good sensitivity to the toxic gases like NO$_2$. Also its properties of good chemical and thermal suability give a potential to superiors gas sensing system. Depositioni of Octa(2-ethyhexyloxy) Copper Phthalocyanine is confirmed by transfers ratio, UB/visible spectra and current-voltage (I-V) characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.10-11
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• 1991

In this paper, Arachidic Acid of long-chain fatty acid was soluted by chloroform and observed $\pi$-A curve in trough. In our experimental result, optimum pressure for fabricating the LB film was 30mN/m. In $\pi$-A curve measurment, temperature dependence was investigated between 20-50($^{\circ}C$). However, in this temperature range, the variation of solid phase pressure was not observed.