• 한국전기전자재료학회논문지
• /
• 제32권2호
• /
• pp.147-150
• /
• 2019

There is a need for the development of transparent conductive materials that are economical and environmentally friendly with exhibit low resistivity and high transmittance in the visible spectrum. In this study, the deposition rate and uniformity of Al-doped ZnO-thin films were improved by changing the Z-motion of the sputtering system. The deposition rate and the uniformity were determined to be 3.44 nm/min and 1.23%, respectively, under the 10 mm Z-motion condition. During $O_2$ plasma treatment, the intrusion-type metal elements in the thin film were reduced, which contributed to an oxygen vacancy reduction in addition to structural stabilization. Moreover, the sheet resistance was more easily saturated.

• Transactions on Electrical and Electronic Materials
• /
• 제12권3호
• /
• pp.110-114
• /
• 2011

Polymeric films of high chemical stability and mechanical strength covered with a thin metallic film have been extensively used in various fields as electric and electronic materials. In this study, we have chosen polypropylene (PP) as the polymer due to its outstanding chemical resistance and good creep resistance. We coated thin nickel film on PP films by the electroless plating process. The surfaces of PP films were pre-treated and modified to increase the adhesion strength of metal layer on PP films, prior to the plating process, by an environment-friendly process with atmospheric plasma generated using dielectric barrier discharges in air. The surface morphologies of the PP films were observed before and after the surface modification process using a scanning electron microscope (SEM). The static contact angles were measured with deionized water droplets. The cross-sectional images of the PP films coated with thin metal film were taken with SEM to see the combined state between metallic and PP films. The adhesion strength of the metallic thin films on the PP films was confirmed by the thermal shock test and the cross-cutting and peel test. In conclusion, we made a composite material of metallic and polymeric films of high adhesion strength.

• 한국전기전자재료학회논문지
• /
• 제22권1호
• /
• pp.81-85
• /
• 2009

We has been analysed optical properties of OLED(organic light emitting diode) and characteristics of ITO(Indium Tin Oxide) in terms of $O_2$ plasma treatment for manufacturing high efficiency OLED, RF power of $O_2$ plasma was changed 25, 50, 100, 200 W. $O_2$ gas flow, gas pressure and treatment time were fixed. Sheet resistance and surface roughness of ITO were measured by Hall-effect measurement system and AFM, respectively. The ranges of sheet resistance and surface roughness were $5.5{\sim}6,06\;{\Omega}$ and $2.438{\sim}3.506\;nm$ changing of RF power, respectively, PM(Passive Matrix)OLED was fabricated with the structure of ITO(plasm treatment)/TPD($400\;{\AA}$)/$Alq_3(600\;{\AA})$/LiF($5\;{\AA}$)/Al($1200\;{\AA}$). Turn-on voltage of PMOLED was 7 V and luminance was $7,371\;cd/m^2$ at the RF power of 25 W, $O_2$ plasma treatment of ITO surface was result in lowering the operating voltage and improving luminance of PMOLED.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제52권5호
• /
• pp.206-206
• /
• 2003

It is hard to expect excellent electrical, mechanical and chemical properties from most of the composite materials presently used as insulators due to insufficient wettability property caused by the difference of interfacial properties between the matrix material and the reinforcer. Therefore, various interfacial coupling agents have been developed to improve the interfacial properties of composite materials. But if the wettable coupling agents are used outdoor for a long time, change in quality takes place in the coupling agents themselves, bringing about deterioration of the properties of the composite materials. In this study, glass surface was treated by plasma to examine the effect of dry interface treatment without coupling agent. It was identified that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. Also, the surface resistance rate and dielectric property were improved.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제52권5호
• /
• pp.206-212
• /
• 2003

It is hard to expect excellent electrical, mechanical and chemical properties from most of the composite materials presently used as insulators due to insufficient wettability property caused by the difference of interfacial properties between the matrix material and the reinforcer. Therefore, various interfacial coupling agents have been developed to improve the interfacial properties of composite materials. But if the wettable coupling agents are used outdoor for a long time, change in quality takes place in the coupling agents themselves, bringing about deterioration of the properties of the composite materials. In this study, glass surface was treated by plasma to examine the effect of dry interface treatment without coupling agent. It was identified that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. Also, the surface resistance rate and dielectric property were improved.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2017년도 춘계학술대회 논문집
• /
• pp.148-148
• /
• 2017

Surface modification is a type of mechanical manipulation skills to achieve extensive aims including corrosion control, exterior appearance, abrasion resistance, electrical insulation and electrical conductivity of substrate materials by generating a protective surface using electrical, physical and chemical treatment on the surface of parts made from metallic materials. Such surface modification includes plating, anodizing, chemical conversion treatment, painting, lining, coating and surface hardening; this study conducted cavitation experiment to assess improvement of durability using anodizing. In order to observe surface characteristics with applied current density, the electrolyte temperature, concentration was maintained at constant condition. To prevent hindrance of stable growth of oxide layer due to local temperature increase during the experiment, stirring was maintained at constant speed. In addition, using galvanostatic method, it was maintained at processing time of 40minutes for 10 to $30mA/cm^2$. The cavitation experiment was carried out with an ultra sonic vibratory apparatus using piezo-electric effect with modified ASTM-G32. The peak-to-peak amplitude was $30{\mu}m$ and the distance between the horn tip and specimen was 1mm. The specimen after the experiment was cleaned in an ultrasonic bath, dried in a vacuum oven for more than 24 hours, and weighed with an electric balance. The surface damage morphology was observed with 3D analysis microscope. As a result of the study, differences were observed surface hardness and anti-cavitation characteristics depending on the development of oxide film with the anodizing process time.

• 한국초전도ㆍ저온공학회논문지
• /
• 제6권4호
• /
• pp.17-21
• /
• 2004

The butt joint was verified to satisfy the thermal stability of the ITER magnet system through the ITER CS model coil test. Since the contact area in the butt joint is limited to the cross section of the cable, it is necessary to analyze and control the joining parameters precisely for improving the DC resistance. It is difficult to simulate the cables, which are composed of a lot of strands, as three-dimensional models using the commercial code. The random numbers were used to simulate many kinds of contact patterns of the strands on the bonding surface for calculating the bonding area and the DC resistance of the butt joint. The calculated DC resistance decreases with an increase of cable filling factor in terminal. The calculated DC resistance of a 0.9 cable filling factor is about 0.48 n-Ohm, which is about one-tenth of that in the CS model coil test when not considering the electrical contact resistance. From this difference, the electrical contact resistance between the strands and copper sheet was calculated.

• 반도체디스플레이기술학회지
• /
• 제14권3호
• /
• pp.51-55
• /
• 2015

We have fabricated silver nanowire (AgNW) films as a stretchable and transparent electrode on polydimethylsiloxane (PDMS) substrates using a spray coater. Inherently, they show poor surface roughness and stretchability. To tackle it, we have employed a conductive polymer, poly (3,4-ethylenedioxythiophene) : Poly(styrene sulfonate) (PEDOT : PSS). PEDTO : PSS solution is mixed with AgNWs or spin-coated on the AgNW film. Compared with AgNW film only, PEDOT : PSS film only, and polymer-mixed AgNW films, the AgNW/polymer bilayer films exhibit much better surface roughness and stretchability. It is found that spray-coating of AgNWs on uncured PDMS and spin-coating of PEDOT : PSS solution on the AgNW films enhance the surface roughness of electrodes. Such a bilayer structure also provides a stable resistance under tensile strain due to the fact that each layer acts as a detour route for carriers. With this structure, we have obtained the peak-to-peak roughness ($R_{pv}$) as low as 76.8nm and a moderate increase of sheet resistance (from $10{\Omega}/{\Box}$ under 0% strain to $30{\Omega}/{\Box}$ under 40% strain).

• 한국전기전자재료학회논문지
• /
• 제37권2호
• /
• pp.208-214
• /
• 2024

This reports the electrical properties of single-crystal β-gallium oxide (β-Ga₂O₃) vertical Schottky barrier diodes (SBDs) with a different guard ring structure. The vertical Schottky barrier diodes (V-SBDs) were fabricated with two types guard ring structures, one is with metal deposited on the Al₂O₃ passivation layer (film guard ring: FGR) and the other is with vias formed in the Al₂O₃ passivation layer to allow the metal to contact the Ga₂O₃ surface (metal guard ring: MGR). The forward current values of FGR and MGR V-SBD are 955 mA and 666 mA at 9 V, respectively, and the specific on-resistance (R_on,sp) is 5.9 mΩ·cm² and 29 mΩ·cm². The series resistance (R_s) in the nonlinear section extracted using Cheung's formula was 6 Ω, 4.8 Ω for FGR V-SBD, 10.7 Ω, 6.7 Ω for MGR V-SBD, respectively, and the breakdown voltage was 528 V for FGR V-SBD and 358 V for MGR V-SBD. Degradation of electrical characteristics of the MGR V-SBD can be attributed to the increased reverse leakage current caused by the guard ring structure, and it is expected that the electrical performance can be improved by preventing premature leakage current when an appropriate reverse voltage is applied to the guard ring area. On the other hand, FGR V-SBD shows overall better electrical properties than MGR V-SBD because Al₂O₃ was widely deposited on the Ga₂O₃ surface, which prevent leakage current on the Ga₂O₃ surface.

• 한국전기전자재료학회논문지
• /
• 제26권5호
• /
• pp.367-372
• /
• 2013

In this paper, micro dried bio-potential electrodes are demonstrated for sEMG (surface ElectroMyoGraphic) signal measurement using conductive epoxy on the textile fabric. Micro dried bio-potential electrodes on the textile fabric substrate have several advantages over the conventional wet/dry electrodes such as good feeling of wearing, possibility of extended-wearing due to the good ventilation. Also these electrodes on the textile fabric can easily apply to the curved skin surface. These electrodes are fabricated by the screen-printing process with the size of $1mm{\times}10mm$ and the resultant resistance of these electrodes have the average value of $0.4{\Omega}$. The conventional silver chloride electrode shows the average value of $0.3{\Omega}$. However, the electrode on the textile fabric are able to measure the sEMG signal without feeling of difference and this electrode shows the lower resistance of $1.03{\Omega}$ than conventional silver chloride electrode with $2.8{\Omega}$ in the condition of the very sharp curve surface (the radius of curvature is 40 mm).