• International Journal of Korean Welding Society
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• v.2 no.1
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• pp.1-10
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• 2002

The thermal contact conductance at different temperatures and with different electrode forces and zinc coating morphology was measured by monitoring the infrared emissions from the one dimensionally simulated contact heat transfer experiments. The contact heat transfer coefficients were presented as a function of the harmonic mean temperature of the two contacting surfaces. Using these contact heat transfer coefficients and experimentally measured temperature profiles, the electrical contact resistivities both for the faying interface and electrode-workpiece interface were deduced from the numerical analyses of the one dimension simulation welding. It was found that the average value of the contact heat transfer coefficients for the material with zinc coating (coating weight from 0 g/$mm^2$to 100 g/$mm^2$) ranges from 0.05 W/$mm^2$$^{\circ}C$ to 2.0 W/$mm^2$$^{\circ}C$ in the temperature range above 5$0^{\circ}C$ harmonic mean temperature of the two contacting surfaces. The electrical contact resistivity deduced from the one dimension simulation welding and numerical analyses showed that the ratio of electrical contact resistivity at the laying interface to the electrical contact resistivity at the electrode interface is smaller than one far both bare steel and zinc coated steel.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.139-141
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• 2015

Contact resistance of interface between the channel layers and various S/D electrodes was investigated by transmission line method. Different electrodes such as Ti/Au, a-IZO, and multilayer of a-IGZO/Ag/a-IGZO were compared in terms of contact resistance, using the transmission line model. The a-IGZO TFTs with a-IGZO/Ag/a-IGZO of S/D electrodes showed good performance and low contact resistance due to the homo-junction with channel layer.

• Journal of Welding and Joining
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• v.26 no.2
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• pp.75-84
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• 2008

With the development of surface roughness textured steel for automotive body-in-white assemble, one of key issues is to understand the role of the surface roughness in textured steel sheets. To investigate effect of surface roughness on weldability in prepared steels, electrode force was varied. Steel sheets (T-H) with high surface roughness ($Ra\;=\;1.94\;{\mu}m$) reduced electrode life. It was attributed to the higher contact resistance at the electrode-sheet interface in the presence of the high surface roughness. The increased electrode diameter decreased current density, therefore reducing weld electrode life due to small weld button size. When an increased electrode force was used, a significant increase in the electrode life was observed in welding of high surface roughness steel sheet. This study suggested that contact resistance at the electrode-sheet interface was the dominant factor, as compared to the sheet-sheet interface for determining electrode life in welding of surface roughness textured steel.

• Carbon letters
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• v.14 no.3
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• pp.171-174
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• 2013

The high quality contact between graphene and the metal electrode is a crucial factor in achieving the high performance of graphene transistors. However, there is not sufficient research about contact resistance reduction methods to improve the junction of metal-graphene. In this paper, we propose a new method to decrease the contact resistance between graphene and metal using directly grown graphene over a metal surface. The study found that the grown graphene over copper, as an intermediate layer between the copper and the transferred graphene, reduces contact resistance, and that the adhesion strength between graphene and metal becomes stronger. The results confirmed the contact resistance of the metal-graphene of the proposed structure is nearly half that of the conventional contact structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.605-608
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• 1999

We report investigations on a Pentacene thin film as a component for active layer of Organic thin film transistors. Pentacene film was deposited by Organic Molecular Beam Deposition(OMBD) and Al electrode was deposoted by vacuum evaporation. Electrical characterization of Pentacene films were measured by the three-terminal contact resistance methods, as the results contact resistance between pentacene films and the Aluminium electrode is 5.064G$\Omega$. The Al contact with the pentacene shows the bottom contact resistance. From the current-voltage characteristics, electrical conductivity of the Pentacene film is found as ~ 10$^{-4}$ /cm. physical characterization of pentacene films were measured by UV-spectrum and Cyclic-Voltammetry method.

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.90-95
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• 2022

The effect of the structure of an ITO nanoparticle film sensor on its performance was studied. A printed ITO film (P-ITO film) was fabricated on a flexible polyethylene terephthalate (PET) substrate, and the contact resistance of the electrode and sensor response change were clarified according to the detection position. The contact resistance between Ag and P-ITO was observed to be -204.4 Ω using the transmission line method (TLM), confirming that a very good ohmic contact is possible. In addition, we confirmed that the contact position of the analyte had a significant influence on the response of the sensor. Based on these results, the performance of the four types of sensors was compared. Consequently, we observed that 1) optimizing the resistance of the printed film, 2) optimizing the electrode structure and analyte input position, and 3) optimizing the electrode area are very important for fabricating a metal oxide nanoparticle (MONP) sensor with optimal performance.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.1
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• pp.44-49
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• 2012

The indirect-contact ECG measurement is a newly developed method for unconstrained and nonconscious measurement in daily Life. This study is the first step to reducing the large background noise appearing in indirect-contact ECG. This study built the thermal noise model of capacitively coupled active electrode which is used in indirect-contact ECG. The results show that the level of thermal noise estimated by the thermal noise model is much the same as that of actual background noise for the capacitively coupled active electrode alone. By applying the actual electrical properties of a sample cotton cloth to the thermal noise model, the theoretical level of thermal noise in the indirect-contact ECG was estimated. The results also show that the level of op-amp's intrinsic noise is so small that it can be negligible in comparison with thermal noise of resistors. The relationship between the level of thermal noise and the resistance of the bias resistor was derived, and it is the base for the further study how to choice the optimal resistance for the bias resistor.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.270-271
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• 2008

The contact resistance between organic semiconductor and source-drain electrode in Bottom Contact Organic Thin-Film Transistors (BCOTFTs) can be effectively reduced by metal oxide/molybdenum double layer structure; metal oxide layers including nickel oxide (NiOx/Mo) and moly oxide(MoOx) under molybdenum work as a high performance carrier injection layer. Step profiles of source-drain electrode can be easily achieved by simultaneous etching of the double layers using the difference etching rate between metal oxides and metal layers.

• New & Renewable Energy
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• v.4 no.2
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• pp.74-80
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• 2008

To improve the blue responses of screen-printed single crystalline silicon solar cells, we investigated an emitter etch-back technique to obtain high emitter sheet resistances, where the defective dead layer on the emitter surface was etched and became thinner as the etch-back time increased, resulting in the monotonous increase of short circuit current and open circuit voltage. We found that an optimal etch-back time should be determined to achieve the maximal performance enhancement because of fill factor decrease due to a series resistance increment mainly affected by contact and lateral resistance in this case. To elucidate the reason for the fill factor decrease, we studied the resistance analysis by potential mapping to determine the contact and the lateral series resistance. As a result, we found that the fill factor decrease was attributed to the relatively fast increase of contact resistance due to the dead layer thinning down with the lowest contact resistivity when the emitter was contacted with screen-printed silver electrode.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.390-393
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• 2008

To improve the blue responses of screen-printed single crystalline silicon solar cells, we investigated an emitter etch-back technique to obtain high emitter sheet resistances, where the defective dead layer on the emitter surface was etched and became thinner as the etch-back time increased, resulting in the monotonous increase of short circuit current and open circuit voltage. We found that an optimal etch-back time should be determined to achieve the maximal performance enhancement because of fill factor decrease due to a series resistance increment mainly affected by contact and lateral resistance in this case. To elucidate the reason for the fill factor decrease, we studied the resistance analysis by potential mapping to determine the contact and the lateral series resistance. As a result, we found that the fill factor decrease was attributed to the relatively fast increase of contact resistance due to the dead layer thinning down with the lowest contact resistivity when the emitter was contacted with screen-printed silver electrode.