• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.61-62
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• 2006

본 연구에서는 대표적인 양친매성분자인 Arachidic acid를 이용하여 박막을 제작하였으며, 층수 변화에 따른 표면이미지와 전압-전류 특성을 측정하였다. Arachidic acid 는 포화지방산으로 ($CH_3(CH_2)_{18}$ COOH)의 구조를 가지며, 크기가 $27.5{\AA}$으로 $CH_3(CH_2)_{18}$의 소수기와 COOH의 친수기로 구성되어 있어, Langmuir-Blodgett (LB) Trough을 사용하여 박막제작과 분자제어가 쉽다. Chloroform을 용매로 하여 2 mmol/l의 농도를 조성하여 ${\pi}$-A 등온선을 통해 기체 상태, 액체 상태, 고체 상태를 관찰하였다. LB 막의 제작 및 평가에서 막의 안정성은 ${\pi}$-A 곡선, AFM(Atomic force microscopy) 등을 통하여 확인하였다. 또한 LB 막을 Metal/유기물 LB막/Metal 구조의 소자로 제작하여 전압-전류 특성을 측정하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.349-352
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• 1999

We have investigated the electrical characteristics of arachidic acid($C_{20}$), stearic acid(C_{18} and palmitic acid($C_{16}$) Langmuir-Blodgett(LB) films because the fatty acid systems have a same hydrophilic group and a different hydrophobic one (alkyl chain length). In this work, fatty acid systems were used as LB films and the status of the deposited films were confirmed by evaluating the capacitance and I-V characteristics. The conductivity of $C_{20}$, C_{18} and $C_{16}$ LB films obtained from I-V characteristics were about 5x $10^{15}$, 3x $10^{14}$ and 9x $10^{14}$[S/cm], espectively. These results have shown the insulating materials and could control the conductivity by changing the length of alkyl chain. Also, we have confirmed that the barrier height of fatty acid systems were about 1.32- 1.40[eV] and the relative dielectric constant were about 2.9~4.2. These values were almost the same ones obtained from dielectric characteristics.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.10
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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.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.374-376
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• 1989

Ultra Tihn Film of 100 angstrom-order is fabricated by Langmuir-Blodgett technique. The conductivity of this this measured by the direction of either vertical or horizontal axis is results in a quite different value. Specific inductive capacity and effect of time variation of LB films are also considered.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.136-138
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• 2005

Merocyanine dye (MD) has been extensively investigated due to its marked potential application to photo-electric devices. We fabricated the number of layers to control its optical characteristics using the Langmuir-Blodgett (LB) method. We evaluated the morphology and optical characteristics of MD LB films using Atomic Force Microscopy (AFM) and UV spectroscopy, PL spectroscopy. As a result, we obtained the quantitative morphology and optical characteristics of LB films from controlling the deposided layers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.556-558
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• 2007

We used an elcosanoic acid material and the material was very famous as an thin film bio and insulating material. Eicosanoic acid monolayer was deposited by Langmuir-Blodgett (LB) technique and a subphase was a $CdCl_2$ solution as a $2\times10^{-4}mol/l$. Also, we used a bottom electrode as an $Al/Al_2O_3$ and a top electrode as a Al. When the positive and negative bias applied to the molecular device, the behavior shows that a tunnel switching characteristics. This results were analyzed regarding various mechanisms.

• Electrical & Electronic Materials
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• v.11 no.10
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• pp.60-65
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• 1998

Deposition conditions, surface morphology, and electrical properties of polyamic acid alkylamine salts (PAAS) Langmuir-Blodgett(LB) films have been investigated through a study of surface pressure-area $\pi$-A isotherms, AFM (atomic force microscopy), and current-voltage characteristics. To obtain the optimum conditions of film deposition, the $\pi$-A isotherms were examined by varying temperature, barrier moving speed, dipping speed, spreading amount of solution etc. The Z-type LB films were made at the surface pressure of 5 mN m-1 and 25 mN m-1 for the AFM study; the former surface pressure forms the gas phase and the latter one forms the solid phase. The LB film made in the gas phase show domains with a size of about 200 A diameter and 70 A height. However, the LB films made in the solid phase show a very smooth surface with 2 A surface roughness. In the current-voltage characteristics measured along the perpendicular direction of the films, ohmic conduction has been observed below 105 V cm-1 and the calculated electrical conductivity is about 10-13 S cm-1. Nonohmic conduction has been observed above = 10-11 V cm and the conduction mechanism can be explained by the Schottky effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.273-276
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• 1997

This paper describes the thermally stimulated current (TSC) measurements of arachidic acid and polyamic acid alkylamine salt(PAAS) LB film, which is a precursor of polyimide(PI). The measurements were performed from room temperature to about 25$0^{\circ}C$ and the temperature was increased at a rate of 0.02 K/s linearly. It shows that peaks of TSC are observed at about 8$0^{\circ}C$ in the arachidic acid and about 8$0^{\circ}C$, 16$0^{\circ}C$ in the PAAS LB films. Results of these measurements indicate that one peak at 8$0^{\circ}C$ is resulted from alkyl group; the other peak at 16$0^{\circ}C$ is due to alkyl and C-O group of PAAS. Additional large peak at about 16$0^{\circ}C$ is due to dipole moments in the PAAS films. The DSC of PAAS, arachidic acid and octadesylamine are measured. Thermal imidization was performed at 30$0^{\circ}C$ for 1 hour by our pre study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.47-50
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• 2000

The optical characteristics of merocyanine dyes have been investigated widely due to their possible application to the high efficiency photo-electric devices. The optical systems are mostly fabricated using vacuum evaporation, casting and Langmuir-Blodgett method and the arrangement and orientation of dye molecules is one of the most important factors in the study on the optical characteristics. In this study, we fabricated the molecular systems through the LB techniques and investigated the optical characteristics of merocyanine dye LB film using the oscillation characteristics of quartz crystal. It was quite interesting behavior that the resistance and frequency shift at the parallel resonance under the UV irradiation.

• Journal of the Korean institute of surface engineering
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• v.28 no.1
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• pp.34-45
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• 1995

An amphiphilic nitroxide radical(2,2'6,6'-tetramethyl-4-octadecyioxy-1-piperidinyloxyl, TEMOPO) or mixture of TEMOPO and arachidic acid(Icosanoic acid, AA), was spread on water surface by the Langmuir-Blodgett(LB) method and surface pressure-area curve was measured. Such monolayer films of TEMOPO were transferred onto surfaces of photo transferable tin oxide electrodes(PTTO) by the LB method under various surface pressure with the transfer ratio of larger than 0.95 at the surface pressure higher than 15mN/m. The electrochemical effect of functional nitroxy radical monolayer onto semi-conductive electrode to electrolyte have been investigated by using LB method. Cyclic voltammetry technique was used for the electrochemical behavior measurement of TEMOPO monolayer onto the PTTO in 0.18 mo1/$dm^3$ $H_2SO_4$ solutions. The shape of voltammograms was found to change from one electrode to another. The amount of charge for the oxidation and the re-reduction of the cation to TEMOPO were evaluated from graphical integration. The amounts of charge were always smaller than those predicted from the $\pi$-$\sigma$ curves though the transfer ratio was unity. The poor reproducibility of the cyclic voltammograms was improved by the mixing with AA. Structure and arrangement of monomolecular layer on water surface and electrode were studied. Characteristics of monolayer film applied for the mediation reaction was also discussed by electrochemical method.