• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.49-54
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• 2001

Monolayers such as self-assembled monolayer (SAM) have received considerable attention to reduce stiction and friction in micro-devices and microelectromechanical systems (MEMS). Various organic molecular films were investigated to obtain better understanding of their tribological behaviors and adhesion property. The organic molecular films studied in this work are: epoxysilane SAMs, octadecyltricholosilane (OST), multi-layers composed of epoxysilane SAMs, poly〔styrene-b-(ethylene-co-butylene)-b-styrene〕(SEBS) and compound of epoxy resin and poly (paraphenylene) (EP/PPP). The pull-off forces of these films were also obtained from force-distance curves measured in static mode of operation of atomic force microscope (AFM). Tribological tests were conducted with a ball-on-flat reciprocating friction tester. The OST showed the lowest pull-off force, indicating its low adhesion property. It was revealed that, the OST, EP/PPP and the multi-layer of epoxysilane SAMs, SEBS and EP/PPP exhibited good tribological properties at the lower load (0.3 N) whereas the OST showed best performance at the higher load (1.8 N).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.56-56
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• 2010

We report a low-temperature fabrication of organic/inorganic nanohybrid dielectrics for organic thin film transistors. The self-assembled organic layers (SAOLs) were grown by repeated sequential adsorptions of C=C-terminated alkylsilane and metal (Al or Ti) hydroxyl with ozone activation, which was called "molecular layer deposition (MLD)". The $TiO_2$ and $Al_2O_3$ inorganic layers were grown by ALD, which relies on sequential saturated surface reactions resulting in the formation of a monolayer in each sequence and is a potentially powerful method for preparing high quality multicomponent superlattices. The MLD method combined with ALD (MLD-ALD) was applied to fabricate SAOLs-$Al_2O_3$-SAOLs-$TiO_2$ nanohybrid superlattices on polymer substrates at relatively low temperature. The MLD method is an ideal fabrication technique for various flexible electronic devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.394-394
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• 2012

We fabricated organic-inorganic superlattice films using molecular layer deposition (MLD) and atomic layer deposition (ALD). The MLD is a gas phase process in the vacuum like to atomic layer deposition (ALD) and also relies on a self-terminating surface reaction of organic precursor which results in the formation of a monolayer in each sequence. In the MLD process, 'Alucone' is very famous organic thin film fabricated using MLD. Alucone layers were grown by repeated sequential surface reactions of trimethylaluminum and ethylene glycol at substrate temperature of $80^{\circ}C$. In addition, we developed UV-assisted $Al_2O_3$ with gas diffusion barrier property better than typical $Al_2O_3$. The UV light was very effective to obtain defect-free, high quality $Al_2O_3$ thin film which is determined by water vapor transmission rate (WVTR). Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of each organic, inorganic film. Composition of the organic films was confirmed by infrared (IR) spectroscopy. Ultra-violet (UV) spectroscopy was employed to measure transparency of the organic-inorganic superlattice films. WVTR is calculated by Ca test. Organic-inorganic superlattice films using UV-assisted $Al_2O_3$ and alucone have possible use in gas diffusion barrier for OLED.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.241-243
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• 1991

The LB technique is one of the most, powerful fabricating methods of organic ultra thin film, which deposits a monolayer film in molecular level onto the surface of the substrate. In order to fabricate the LB film with optimal condition, we have to deposite monolayer film at optimum depositing pressure. which is dependent on the kind of deposit materials. ${\pi}-A$ curve is one of the most important, criteria to determine the optimum pressure. In this paper, we obtained that the optimum pressure is $20{\sim}50(mN/m)$ from ${\pi}-A$ curve of the stearic acid. In our experiments, it was known that LB ultra thin film is deposited beat at 30(mN/m) by checking the characteristics of LB film.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1708-1710
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• 2000

The synthesis and characterization of polymers for organic Metal/Insulator/Metal(MIM) devices were investigated from LB films. The physicochemical properties of the LB films were examined by UV absorption spectrum and AFM. The AFM images showed for network structure of polyurethane monolayer that the film formed an unsymmetry mesh with intermolecular interaction within the large scale. The stable images are probably due to a strong interaction between the monolayer film and Si substrate. We are unable to obtain molecular 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 Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05c
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• pp.9-13
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• 2004

In this paper, evaluation of physical properties about dielectric relaxation phenomena by the detection of the surface pressures and displacements current on the monolayer films of phospolipid monomolecular DLPC, DMPC using pressure stimulus. As a result, the changed surface pressure, displacement current and the transition forms of dipole moment of phospolipid monomolecular in area per molecular by pressure stimulus were conformed well. It was known that the monolayers by linear relationship for decision of dielectric relaxation time between compressure speed and molecule area By according to the linear relationship relation get that frictional constant, DLPC was $1.89{\times}10^{-19}$[Js] and DMPC was $0.722{\times}10^{-19}$[Js]. It is found that the phospolipid monolayer of dielectric relaxation takes a little time and depend on the molecular area.

• Journal of the Korean institute of surface engineering
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• v.23 no.4
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• pp.197-207
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• 1990

Atomic layer epitaxy is a relatively new epitaxial pprocess chracterized by the alternate and separate exposure of a susbstrate surface to the reactants contaning the constituent element of a compound semicoductror. The ideal ALE is expected to provide sevral advantageous as petcts for growing complicated heterostrutures such as relativly easy controls of the layer thinkness down to a monolayer and in forming abrupt heterointerfaces though monolayer self-saturatio of the growth. In addition, since ALE is stongly dependent on the surface reaction, the growth can also be controlled by photo-excitation which provides activation can be energies for each step of the reaction paths. The local growth acceleration by photo-excitation can be exploited for growing several device strures on the same wafer, which provides another important practical advantage. The ALE growth of GaAs has advanced to the point the laser opertion has been achieved from AlGs/GaAs quantun well structures where thee active layers were grown by thermal and Ar-laser assisted ALE. The status of the ALE growth of GaAs and other III-V compounds will be reviewed with respect to the growth saturation behavior and the electrical properties of the grown crystals.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.487-490
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• 1999

The Maxwell displacement current was generated from 4-octyl-4'-(5-carboxyl-pentamethyleneoxy)- azobenzene (denoted as 8A5H) monolayer Langmuir-Blodgett films prepared on Cr/Au-coated glass substrates due to trans-cis photoisomerization of 8A5H by application of alternate irradiation with UV light and Visible light. The displacement current was generated due to the trans-to-CIS photoisomerization by irradiation with ultraviolet light($\lambda_1$=360nm). Whereas the displacement current was generated in the opposite direction due to the cis-to-trans photoisomerization by photoirradiation with visible light($\lambda_2$=450nm). Finally, We concluded that Displacement current change according to power capacity photoirradiation, the more higher generate the more higher power capacity magnitude.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.491-494
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• 2000

Conductive Langmuir-Blodgett(LB) films have recently attracted much interest from the viewpoint of ultrathin film conductors at the molecular level. The result shows that the Maxwell-displacement-current(MDC) measuring technique is useful in the detection of phase-transition over the entire range of molecule areas. At the liquid-solid phase transition, a striking feature in the present current measurement was observed; the I-A isotherm for a DPPC monolayer has sharp bend. Dynamic behavior of monolayers in the presence of an external field was also investigated using the current-measuring technique. Dynamic behavier of DPPC monolayer was measured by displacement current when the molecules are stimulated by pressure velocity. As result, it is known that current is generated of higher current pe마 as compression velocity become faster. Also, in order to clarify the reorganization of the lipid monolayers, it is instructive to plot the relationship between I and 1/$A^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.365-366
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• 2007

The dendrimer has been well known as a promising macromolecules for a building the organized nanostructure, which of the size can be controlled and which of periphery can be terminated by various functionalities. Currently a variety of research is being carried out in the field of dendrimer / polymer characterization, nano-scale atomic manipulation, and supramolecular nanostructure analysis. We investigated monolayer behavior and its characteristics at the air-water interface by LB method. In this report, we will present the interfacial properties of dendrimer monolayers on various conditions such as the surface-pressure, barrier speed and spreading quantity.