• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.118-121
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• 2002

Polyvinylidene di-fluoride (PVDF) film sensor appeared to be practically useful for the structural health monitoring of composite materials and structures. PVDF film sensors were either attached to or embedded in the graphite/epoxy composite (CFRP) samples to detect the fatigue damage at the bondline of single-lap joints or the tensile failure of unidirectional laminates. PVDF sensors were sensitive enough to detect and determine the crack front in linear location since composites usually produce very energetic acoustic emission (AE). PVDF sensors are extremely cost-effective, as flexible as other plastic films, in low profile as thin as a few tens of microns, and have relatively wide-band response, all of which characteristics are readily utilized for the structural health monitoring of composite structures. Signals due to fatigue damage showed a characteristics of mode II (shear) type failure whereas those from fiber breakage at DEN notches showed that of mode I (tensile) type fracture.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.112-112
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• 2010

Zinc Oxide (ZnO) thin-films were deposited according to the magnetron sputtering method. The deposited ZnO films were annealed with RTA equipment at various annealing temperatures in an vacuum ambient. The influence of the annealing temperature on the structural, electrical, and optical properties of the ZnO films was experimentally investigated, and the effect of conductivity of the ZnO active layer on the device performance of the oxide-TFT was tested. As a result, an increase of the annealing temperature was attributed to improvements of crystallinity in ZnO films. The grain size was found to lead to an increase of conductivity in the ZnO films. Fabricated ZnO TFTs with annealed ZnO active layer provided good performance in the TFT devices. Consequently, the performance of the TFT was determined by the conductivity of the ZnO film, which was related to the structural properties of the ZnO film.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.329.1-329.1
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• 2014

In this paper, we report electrical, optical and structural properties of Al-doped zinc oxide (AZO) thin films deposited at different substrate temperatures and pressures. The films were prepared by radio frequency (RF) magnetron sputtering on glass substrates in argon (Ar) ambient. The X-ray diffraction analysis showed that the AZO films deposited at room temperature (RT) and 20 Pa were mostly oriented along a-axis with preferred orientation along (100) direction. There was an improvement in resistivity ($3.7{\times}10^{-3}{\Omega}-cm$) transmittance (95%) at constant substrate temperature (RT) and working pressure (20 Pa) using the Hall-effect measurement system and UV-vis spectroscopy, respectively. Our results have promising applications in low-cost transparent electronics, such as the thin-film solar cells and thin-film transistors due to favourable deposition conditions. Furthermore our film deposition method offers a procedure for preparing highly oriented (100) AZO films.

• Journal of the Korean institute of surface engineering
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• v.22 no.1
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• pp.17-25
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• 1989

The structural Charactesties and adhesion of chemically vapor deposited TiN film on stain less steels have been investated as functions of deposition temperature, surface roughness of sub state, and types of substrates. The grain zine and the lattice parameter of TiN film decreased with decreasing roughness of substates. The(200) preferred orientation was developed dominatly and the lattlice parameter decreased as temperature intereased reardless of the surdless roughnessand type of the substrates used. The surface morphology of TiN film changed from bushed crystal to a plate and then to pyamidal dense crystals with an increase in the deposition temperature. The adhesion of TiN films increased with coating thinkness and decreased with surface roughness in general. The calculations using a Bejamin & Weaver's model have been compard. Maximum valuse of adhesion energy calculated using Laguier's model were W304=331Jm-2,w410=113Jm-2,andW430=107jm-2

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.136-138
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• 2012

The electrical characteristics of complex films composed of poly(ethylene oxide) (PEO) and urea as a function of the urea concentration were examined in this study. Moreover, their structural characteristics were also compared. Depending on the urea concentration, the structural phases were classified as PEO+${\beta}$-phase composite, ${\beta}$-phase+${\alpha}$-phase composites, or ${\alpha}$-phase composite+urea. At urea concentrations below ~0.064 M, the ${\beta}$-phase was dominant in the complex film. Moreover, the conductance increased rapidly with an increase in the urea concentration. For urea concentrations ranging from ~0.064 to ~0.25 M, the ${\beta}$-phase was gradually substituted by the ${\alpha}$-phase. As the film was composed entirely of the ${\alpha}$-phase at urea concentrations greater than ~0.25 M, its conductance was decreased. In this study, the electrical characteristics observed for the different phases are analyzed and discussed.

• Textile Coloration and Finishing
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• v.2 no.2
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• pp.1-6
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• 1990

In order to investigate the fine structural changes of poly (ethylene terephthalate) film by hydrazinolysis, PET was treated with hydrazine hydrate in methanol at $30^{\circ}C$ for various times. Initially apparent crystallite size and degree of orientation are increased and then, gradually decreased with hydrazinolysis. According to thermoluminescence measurement, trap site decreased by dissolution and then gradually increased with growth of defect in structure. Maximum peak temperature of tan and dynamic loss modulus E" upon hydrazinolysis shifted to the lower temperature in the progress of hydrazinolysis.ysis.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1366-1370
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• 2001

Thin films of the SiO2-TiO2-PDMS composite material have been prepared by the sol-gel dip coating method. Acid catalyzed solutions of tetraethoxy silane (TEOS) and polydimethyl siloxane (PDMS) mixed with titanium isopropoxide Ti(OiPr) were used as precursors. The optical and structural properties of the organically modified 70SiO2-30TiO2 composite films have been investigated with Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible Spectroscopy (UV-Vis), Differential Thermal Analysis (DTA) and prism coupling technique. The films coated on the soda-lime-silicate glass exhibit 450-750 nm thickness, 1.56-1.68 refractive index and 88-94% transmittance depending on the experimental parameters such as amount of PDMS, thermal treatment and heating rate. The optical loss of prepared composite film was measured to be about 0.34 dB/cm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.1
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• pp.33-38
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• 2021

Using facing target magnetron sputtering (FTMS) with a graphite target source, carbon nitride thin films were deposited on silicon and glass substrates at different substrate temperatures to confirm the tribological, electrical, and structural properties of thin films. The substrate temperatures were room temperature, 150℃, and 300℃. The tribology and electrical properties of the carbon nitride thin films were measured as the substrate temperature increased, and a study on the relation between these results and structural properties was conducted. The results show that the increase in the substrate temperature during the fabrication of the carbon nitride thin films increased the hardness and elastic modulus values, the critical load value was increased, and the residual stress value was reduced. Moreover, the increase in the substrate temperature during thin-film deposition was attributed to the improvement in the electrical properties of carbon nitride thin film.

• Korean Journal of Materials Research
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• v.27 no.8
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• pp.403-408
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• 2017

We investigated the effect of ZnO buffer layer on the formation of ZnO thin film by ultrasonic assisted spray pyrolysis deposition. ZnO buffer layer was formed by wet solution method, which was repeated several times. Structural and optical properties of the ZnO thin films deposited on the ZnO buffer layers with various cycles and at various temperatures were investigated by field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence spectrum analysis. The structural investigations showed that three-dimensional island shaped ZnO was formed on the bare Si substrate without buffer layers, while two-dimensional ZnO thin film was deposited on the ZnO buffer layers. In addition, structural and optical investigations showed that the crystalline quality of ZnO thin film was improved by introducing the buffer layers. This improvement was attributed to the modulation of the surface energy of the Si surface by the ZnO buffer layer, which finally resulted in a modification of the growth mode from three to two-dimensional.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.1
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• pp.23-27
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• 2003

Structural properties of Cu-Ni alloy films, such as preferred orientation, crystallite size, in-ter-planar spacing, cross-sectional morphology, and electrical resistivity, are investigated in terms of tar-get configurations that are used in the film deposition by means of magnetron co-sputtering. Two different target configurations are considered in this study: a dual-type configuration in which two separate tar-gets (Cu and Ni) and different bias types (RF and DC) are used and a Ni-on-Cu type configuration in which Ni chips are attached to a Cu target. The dual-type configuration appears to have some advantages over the Ni-on-Cu type regarding the accurate control of atomic composition of the deposited Cu-Ni alloy. However, the dual-type-produced film exhibits a porous and columnar structure, the relatively large internal stress, and the high electrical resistivity, which are mainly due to the relatively low mobility of adatoms. The affects of thermal treatment and deposition conditions on the structural and electrical properties of dual-type Cu-Ni films are also discussed.