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Mirang Park - One of the best experts on this subject based on the ideXlab platform.

  • thickness dependence of electrical properties of ito film deposited on a plastic Substrate by rf magnetron sputtering
    Applied Surface Science, 2006
    Co-Authors: Mirang Park
    Abstract:

    Abstract Indium tin oxide (ITO) films with various thicknesses in range of 40–280 nm were prepared onto a plastic Substrate (PMMA). Deposition was carried out with RF magnetron sputtering method and the Substrate temperature was held at ∼70 °C, in lack of the thermal damage to the Polymer Substrate. Changes in microstructure and electrical properties of ITO films according to their thicknesses were investigated. It was found that amorphous layer with thickness of 80 nm was formed at the interface on the Polymer Substrate and polycrystalline ITO could be obtained above the thickness. Conductivity of ITO films was found to be strongly dependent on the crystallinity. Consequently, it is suggested that crystallinity of the deposited films should be enhanced at the initial stage of deposition and the thickness of amorphous region be reduced in order to prepare high quality ITO thin films on Polymer Substrates.

  • preparation of high quality ito films on a plastic Substrate using rf magnetron sputtering
    Surface & Coatings Technology, 2006
    Co-Authors: Mirang Park
    Abstract:

    Indium tin oxide (ITO) thin films were prepared on a plastic Substrate (PMMA) by RF magnetron sputtering. A novel deposition system where the plasma deposition region and the resistive heating region are separated in space to minimize the thermal damage to the Polymer Substrate was utilized. The effects of intentional heating and oxygen addition on microstructure and electrical transport properties of ITO films were investigated. Conductivity of ITO films was found to be strongly dependent on their crystallinity. High conductive (sheet resistance ∼ 19 Ω/sq) and transparent (above 85%) ITO thin films (150 nm) could be obtained with a moderate heating of Substrate (about 70 °C) and without introduction of oxygen gas during the deposition. It was observed that amorphous layer with thickness of ∼ 80 nm was formed at the interface on the Polymer Substrate and polycrystalline ITO was deposited above this thickness. Dependence of the electrical resistivity of ITO films on their thickness was also discussed.

Haksung Kim - One of the best experts on this subject based on the ideXlab platform.

  • two step flash light sintering of copper nanoparticle ink to remove Substrate warping
    Applied Surface Science, 2016
    Co-Authors: Chung Hyeon Ryu, Sungjun Joo, Haksung Kim
    Abstract:

    Abstract A two-step flash light sintering process was devised to reduce the warping of Polymer Substrates during the sintering of copper nanoparticle ink. To determine the optimum sintering conditions of the copper nanoparticle ink, the flash light irradiation conditions (pulse power, pulse number, on-time, and off-time) were varied and optimized. In order to monitor the flash light sintering process, in situ resistance and temperature monitoring of copper nanoink were conducted during the flash light sintering process. Also, a transient heat transfer analysis was performed by using the finite-element program ABAQUS to predict the temperature changes of copper nanoink and Polymer Substrate. The microstructures of the sintered copper nanoink films were analyzed by scanning electron microscopy. Additionally, an X-ray diffraction and Fourier transform infrared spectroscopy were used to characterize the crystal phase change of the sintered copper nanoparticles. The resulting two-step flash light sintered copper nanoink films exhibited a low resistivity (3.81 μΩ cm, 2.3 times of that of bulk copper) and 5B level of adhesion strength without warping of the Polymer Substrate.

  • two step flash light sintering process for crack free inkjet printed ag films
    Journal of Micromechanics and Microengineering, 2013
    Co-Authors: Sunghyeon Park, Dong Jun Lee, Shin Jang, Haksung Kim
    Abstract:

    In this paper, a two-step flash light sintering process for inkjet-printed Ag films is investigated with the aim of improving the quality of sintered Ag films. The flash light sintering process is divided into two steps: a preheating step and a main sintering step. The preheating step is used to remove the organic binder without abrupt vaporization. The main sintering step is used to complete the necking connections among the silver nanoparticles and achieve high electrical conductivity. The process minimizes the damage on the Polymer Substrate and the interface between the sintered Ag film and Polymer Substrate. The electrical conductivity is calculated by measuring the resistance and cross-sectional area with an LCR meter and 3D optical profiler, respectively. It is found that the resistivity of the optimal flash light-sintered Ag films (36.32 n? m), which is 228.86% of that of bulk silver, is lower than that of thermally sintered ones (40.84 n? m). Additionally, the polyimide film used as the Substrate is preserved with the inkjet-printed pattern shape during the flash light sintering process without delamination or defects.

  • pulsed light sintering characteristics of inkjet printed nanosilver films on a Polymer Substrate
    Journal of Micromechanics and Microengineering, 2011
    Co-Authors: Dong Jun Lee, Sunghyeon Park, Shin Jang, Haksung Kim, Yong Won Song
    Abstract:

    In this work, the microstructures of inkjet-printed nanosilver films sintered by intense pulsed light (IPL) were systematically analyzed and correlated with the electrical properties. Nanosilver films with various dimensions were inkjet-printed and sintered at different light intensities to investigate the effects of the film dimension and light intensity on the sintering characteristics. For comparison purposes, the same inkjet-printed films were also thermally sintered at 210 °C for 1 h. Consecutive light pulses from a xenon lamp induced film swelling and the corresponding hollow microstructures of the inkjet nanosilver films. The resistance of IPL-sintered films was inversely proportional to the light intensity, and the resultant conductivity comparable to the thermally sintered one was achieved within just a few tens of ms, without damaging a Polymer Substrate. While all the thermally sintered patterns experienced shrinkage during the sintering process, the IPL-sintered ones could keep their initial dimension at a certain light intensity.

Masahiro Fukumoto - One of the best experts on this subject based on the ideXlab platform.

  • cold spray coating deposition mechanism on the thermoplastic and thermosetting Polymer Substrates
    Journal of Thermal Spray Technology, 2013
    Co-Authors: Amirthan Ganesan, Motohiro Yamada, Masahiro Fukumoto
    Abstract:

    Cold spraying is a successful and promising coating technique for many engineering applications due to its high-rate and high-dense coating development abilities. Nevertheless, their practical use in Polymer Substrate is still in the fledgling phase. There are very few articles about the cold spray coating on Polymers; however, the interaction of metallic particle with the Polymer Substrate is poorly understood, and thus a thick coating has not successfully been developed on the Polymer Substrate. In order to rationalize as full as possible the entire behavior of the high velocity particle with the Polymer Substrate, we used thermoplastic and thermosetting Polymer materials as Substrates. The particle behaviors with the Substrate were observed under various gas pressure and temperature, and with various particles feed rate. The result showed that the particle behaviors were unique with respect to the Substrate. Also it was clearly understood that the metal particles not experienced any plastic deformation due to the soft nature of the Polymer Substrates. The particles attached to the thermoplastic Substrate either through adhesive bonding and/or mechanical inter locking, whereas only pure localized fracture observed on the thermosetting Substrate and thus no particles attached firmly on the Substrate.

  • bonding behavior studies of cold sprayed copper coating on the pvc Polymer Substrate
    Surface & Coatings Technology, 2012
    Co-Authors: Amirthan Ganesan, Motohiro Yamada, Jon Affi, Masahiro Fukumoto
    Abstract:

    Abstract Metallization of the Polymer surface by cold spray technique is an attractive way of improving their electrical conductivity and erosive resistance properties. However, it is still challenging to achieve a dense and thick high-strength metal coating, such as copper, on the Polymer surface by cold spray system, due to excessive surface erosion during the processing. In order to overcome these difficulties, in the present work, two different types of interlayers are proposed. The polyvinyl chloride (PVC) Polymer Substrate was initially coated with a spherical copper powder and a tin powder separately and then a thick copper coating was fabricated using a dendritic copper powder. The properties of the coatings, such as shear adhesion strength, Vickers hardness and electrical resistivity, were measured and the influence of the interlayer on the above properties and bonding behavior was studied using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and focused ion beam dissection (FIB) techniques. The results show that the deposition efficiency is highly sensitive to the glass transition temperature of the Substrate, irrespective of the process gas pressure. The coating with spherical copper interlayer shows poor shear adhesion strength due to the dislodged Polymer debris at the spherical/dendritic copper coating interface. The electrical conductivity of the coating is fairly low as compared to the bulk copper due to the pores and inter-particle defects.

Stefano Pandini - One of the best experts on this subject based on the ideXlab platform.

  • Mechanical behavior of strain sensors based on PEDOT:PSS and silver nanoparticles inks deposited on Polymer Substrate by inkjet printing
    Sensors and Actuators A: Physical, 2016
    Co-Authors: Michela Borghetti, M. Serpelloni, Emilio Sardini, Stefano Pandini
    Abstract:

    Recently, inkjet printing technology has received growing attention as a method to produce low-cost large-area electronics, sensors, and antennas on Polymer Substrates. This technology relies on printing techniques to deposit electrically functional materials onto Polymer Substrates to fabricate electronic components or sensing elements. In this paper, we applied an inkjet printed technology for the development and characterization of films on a Polymer Substrate aiming at giving design considerations for the optimization of strain sensors or printed electronics obtained by inkjet printing. Two inks were tested over a polyimide Substrate, a water-based conductive Polymer, PEDOT:PSS, and a silver nanoparticles ink. Their sensing capabilities were investigated under tensile conditions and various strain histories (strain ramp; cyclic loading-unloading tests; application of constant strain over prolonged time) aiming at highlighting the correlation between electrical response, applied strain, time and mechanical histories. Furthermore, the mechanical viscoelastic response of the Substrate was investigated under similar strain histories interpreting the results at the light of the Substrate deformational characteristics and evaluating its influence.

T Ota - One of the best experts on this subject based on the ideXlab platform.