• Journal of the Korea Institute of Military Science and Technology
• /
• v.6 no.3
• /
• pp.44-53
• /
• 2003

Cu/C films were prepared at room temperature under $Cu(hfac)_2-Ar-H_2$ atmosphere in order to obtain metallized polymer by using ECR-MOCVD(Electron Cyclotron Resonance Metal Organic Chemical Vapor Deposition) coupled with a DC bias system. The room temperature MOCVD on polymer substrate could be possible by collaboration of ECR and a DC bias. Structural analysis of the films by ECR was found that fine copper grains embedded in an amorphous polymer matrix with indistinctive interfacial layer. The increase in $H_2$ contents brought on copper-rich film formation with low electric resistance. On the other hand carbon-rich films with low sheet electric resistance were prepared in argon atmosphere. The electric sheet resistance of Cu/C films with good interfacial property were controlled at $10^8$~$10^0$ Ohm/sq. ranges by the $H_2$/Ar mole ratio and the shielding effectiveness of the film showed maximum up to 45dB in the our experimental range.

• Journal of the Microelectronics and Packaging Society
• /
• v.30 no.3
• /
• pp.111-118
• /
• 2023

MXene, a two-dimensional transition metal carbide or nitride, has recently attracted much attention as a lightweight and flexible electromagnetic shielding material due to its high electrical conductivity, good mechanical strength and thermal stability. In particular, the Ti-based MXene, Ti₃C₂T_x and Ti₂CT_x are reported to have the best electrical conductivity and electromagnetic shielding properties in the vast MXene family. Therefore, in this study, Ti₃C₂T_x and Ti₂CT_x films were prepared by vacuum filtration using Ti₃C₂T_x and Ti₂CT_x dispersions synthesized by interlayer metal etching and centrifugation of Ti₃AlC₂ and Ti₂AlC. The electrical conductivity and electromagnetic shielding efficiency of the films were measured after heat treatment at high temperature. Then, X-ray diffraction and photoelectron spectroscopy were performed to analyze the structural changes of Ti₃C₂T_x and Ti₂CT_x films after heat treatment and their effects on electromagnetic shielding. Based on the results of this study, we propose an optimal structure for an ultra-thin, lightweight, and high performance MXene-based electromagnetic shielding film for future applications in small and wearable electronics.

• Fibers and Polymers
• /
• v.2 no.4
• /
• pp.171-177
• /
• 2001

Change of tensile properties, electrical conductivity and microwave shielding of electrochemically synthesized polypyrrole films with time are presented. Highly doped films had good electrical stability, retaining high microwave reflectivity throughout the aging period. Lightly doped films were less stable and partially reflective and absorptive of microwaves. FT-IR spectral observations revealed a progressive increase in intensity of an unsaturated conjugated carbonyl peak, which was not observed in the highly doped films, suggesting that the concentration of the dopant had an influence on mechanism of degradation of conductivity.

• Journal of the Semiconductor & Display Technology
• /
• v.12 no.2
• /
• pp.51-56
• /
• 2013

Even if transmissions through normal channel between ubiquitous devices and terminal readers are encrypted, any extra sources of information retrieved from encrypting module can be exploited to figure out the key parameters, so called side channel attack. Since side channel attacks are based on statistical methods, making side channel signal weak or complex is the proper solution to prevent the attack. Among many countermeasures, shielding the electromagnetic signal and adding noise to the EM signal were examined by applying different thicknesses of thin films of ferroelectric (BTO) and conductors (copper and gold). As a test vehicle, chip antenna was utilized to see the change in radiation characteristics: return loss and gain. As a result, the ferroelectric BTO showed no recognizable effect on both shielding and adding noise. Cu thin film showed increasing shielding effect with thickness. Nanometer Au exhibited possibility in adding noise by widening of bandwidth and red shifting of resonating frequencies.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2011.05a
• /
• pp.205-206
• /
• 2011

Cu thin films for electromagnetic wave shielding were prepared on PET film and Ni-coated PET film by using Dry and Wet coating method, such as evaporation method, DC sputtering method and copper sulfate($CuSO_4$). After that, Zn thin film and Ni thin film were prepared onto the Cu thin films by using evaporation dry process and Ni electro plating wet process as a finishing treatment, respectively. The result of conductivity test and corrosion resistance test revealed Cu thin films which were formed with bigger grain size and high Cu composition rate have superior properties. Zn thin film by dry evaporation process and Ni thin film by wet electro plating process on Cu thin films were largely contributed to corrosion resistance. However, Ni thin film by wet process made conductivity of all specimen worse, the other hand, Zn thin film by dry process made it better to improve condictivity of specimens just prepared by dry process.

• Journal of the Korean institute of surface engineering
• /
• v.47 no.5
• /
• pp.269-274
• /
• 2014

Electroless plating process as a solution deposition method is a viable means of preparing conductive metal films on non-conducting substrates through chemical reactions. In the present study, the preparation and properties of electroless Ni-plating on flexible silicone rubber are described. The process has been performed using a conventional Ni(P) chemical bath. Additives and complexing agents such as ammonium chloride and glycine were added and the reaction pH was controlled by NaOH aqueous solution. Ni deposition rate and crystallinity have been found to vary with pH and temperature of the plating bath. It was shown that Ni-films having the high crystallinity, enhanced adhesion and optimum electric conductivity were formed uniformly on silicone rubber substrates under pH 7 at $70^{\circ}C$. The conductive Ni-plated silicone rubber showed a high electromagnetic interference shielding effect in the 400 MHz-1 GHz range.

• Journal of the Korean Society of Radiology
• /
• v.17 no.3
• /
• pp.441-447
• /
• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2004.02a
• /
• pp.99-99
• /
• 2004

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.27-27
• /
• 2009

Non-stochiometric CdS:H films grown on polyethersulfon (PES) flexible polymer substrates at room temperature by R.F. sputtering technique. They exhibited a dark- and photo-sheet resistance of $2.7\times10^5$ and $\sim\;50\;{\Omega}$/square, respectively. These values were realized by an optimum control of both hydrogen doping-levels and the surface morphologies of the films. The comparison between the real and the simulated results for the shielding and the transmission by the free space measurement system in the X-band frequency range (8.2 - 12.4 GHz) was also addressed in this study. Samples overlapped with 13 layers of CdS:H/PES were consistent with the transmission results of pure aluminum metal films ($0.1\;{\Omega}$/square) deposited on PES substrates. As a result, by the simples tacking of the CdS:H/PES layers, the perfect control of the shielding and the transmission of the EM wave in the range of X-band frequency is possible by avisible light alone, and their results are especially very outstanding findings in the stealth function of the radome(Radar+Dome) such as aircrafts, ships, and missiles.

• Electrical & Electronic Materials
• /
• v.10 no.7
• /
• pp.713-718
• /
• 1997

Polyaniline free standing films cast from N-methyl-2-pyrrolidinone(NMP) solution, camphorsulfonic acid(HCSA), dodecylbenzensulfonic acid(HDBSA), inorganic matter(carbon black, graphite) and metal(silver) were prepared by processings. The properties of these films such as crystallinity, near-infrared absorption spectra and conductivity were investigated. The HCSA and HDBSA doped polyaniline films cast from m-cresol and chloroform solvents showed the metallic property and high crystallinity, respectively. The value of conductivity in the HCSA doped polyaniline film obtained 180 S/cm. We have obtained the value of conductivity 200 S/cm in the metal(silver) doped polyaniline film, which is higher than that of the HCSA doped polyaniline film. The metal(silver) doped polyaniline film shows good properties as a electromagnetic shielding material.