• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.53.2-53.2
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• 2011

Dye-sensitized solar cells(DSSCs) have been recognized as an alternative to the conventional p-n junction solar cells because of their simple fabrication process, low production cost, and transparency. A typical DSSC consists of a transparent conductive oxide (TCO) electrode, a dye-sensitized oxide semiconductor nanoparticle layer, liquid redox electrolyte, and a Pt-counter electrode. In dye-sensitized solar cells, charge recombination processes at interfaces between coducting glass, $TiO_2$, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. A layer of ZTO thin film less than ~200nm in thickness, as a blocking layer, was deposited by DC magnetron sputtering method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells(DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte ($I^-/I_3^-$). The presented DSCs were fabricated with working electrode of Ga-doped ZnO glass coated with blocking ZTO layer, dye-attached nanoporous $TiO_2$ layer, gel electrolyte and counter electrode of Pt-deposited GZO glass. The effects of blocking layer were studied with respect to impedance and conversion efficiency of the cells.

• Journal of the Korean Magnetics Society
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• v.10 no.6
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• pp.280-294
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• 2000

[(300nm)Ta/(500nm)NdFeB/(300nm)Ta] thin films were deposited at 5 mTorr Ag gas pressure by RF-DC magnetron sputtering, and their magnetic properties were investigated. The [Ta/NdFeB/Ta] films deposited on heated Si substrates showed high perpendicular anisotropy and excellent hard magnetic properties. The films sputtered at tile substrate temperature of T$\sub$s/=650$^{\circ}C$ and 700$^{\circ}C$ showed (BH)$\sub$max/=20 MGOe and $\sub$i/H$\sub$c/= 18.9 kOe along the perpendicular direction to the film plane, respectively.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.46-48
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• 2004

A micro-scale discharge device has been fabricated using MEMS technology and failure mechanisms during DC discharge are investigated for the microstructure. The failure of sustaining the plasma is mainly caused by either open or short of the micro-electrodes, both resulting from the sputtered metal atoms during the DC discharge. The glow discharge lifetime of the microstructures is found to depend on bias circuit scheme as well as the electrode structure. Based on the understanding of the failure mechanism, a novel microstructure is suggested to improve discharge lifetime and the longer lifetime is experimentally demonstrated. In addition to the failure mechanism, an electric breakdown between two electrodes with microns gap are studied using micromachined metal structures. The electrode gap is able to be accurately controlled by thickness of a sacrificial layer and the electric breakdown was measured while varying the gap from $2{\mu}m$ to $20{\mu}m$. The electric breakdown behavior was found to highly depend on the electrode material, which was not considered in Paschen's law.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.228-230
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• 1994

A Spotter ion Plating(SIP) system with a r. f. coil electrode and the Facing Target Sputter(FTS) source was designed for high-quality thin film formation. The rf discharge was combined with DC facing target sputtering in order to enhance ionization degree of a sputtered atoms. The discharge voltage-discharge characteristics curves of a FTS source could be characterized by the fern of $I{\propto}V^n$ with n in the range of $8{\sim}12$. The energy of ions incident on the substrate depended on the sheath potential of DC biased substrate. The mean impact ion energy increased with negative bias voltage and rf power. The adhesive force of the TiN film formed was in the range of $30{\sim}50N$, and markedly influenced by substrate bias voltage.

• Journal of Magnetics
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• v.2 no.1
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• pp.22-24
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• 1997

FeN thin films were deposited by RF-reactive diode sputtering to investigate magnetic characteristics variation due to substrate tilt during the film deposition, and their magnetic properties were measured by VSM, SEM and AFM. When the substrate tilt pivot edges were parallel to the applied field, the magnetic anisotropy was increased When the substrate tilt pivot edges were perpendicular to the applied field, the easy magnetization axis became the hard magnetization axis, and the hard axis became the easy axis as the tilt angles were increased. The reason is believed to be due to the fact that the tilt induced shape magnetic anisotropy became larger than the field induced magnetic anisotropy by DC magnetic field as the crystal grains are enlongated along the substrate tilt pivot edges due to "oblique incidence anisotropy" commonly found in eveporated thin films.

• Transactions on Electrical and Electronic Materials
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• v.5 no.3
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• pp.122-125
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• 2004

ITO films were deposited on polyethylene terephthalate substrate by a dc reactive magnetron sputtering using rf bias without substrate heater and post-deposition thermal treatment. The dependency of rf substrate bias on plasma sputter processing was investigated to control energetic particles and improve ITO film properties. The substrate was applied negative rf bias voltage from 0 to -80 V. The composition of indium, tin, and oxygen atoms is strongly depended on the rf substrate bias. Oxygen deficiency is the highest at rf bias of -20 V. The electrical and optical properties of ITO films also are dominated obviously by negative rf bias.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.252-252
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• 2009

• Transactions on Electrical and Electronic Materials
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• v.5 no.4
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• pp.153-157
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• 2004

ITO thin films were deposited on PET and soda-lime glass substrates by a dc reactive magnetron sputtering of In-Sn alloy metal target without substrate heater and post-deposition thermal treatment. The dependency of rf-bias voltage and substrate power during deposition processing was investigated to control the electrical and optical properties of ITO films. The range of rf bias voltage is from 0 to -80 V and the substrate power is applied from 10 to 50 W. The minimum resistivity of ITO film is 5.4${\times}$10$^{-4}$ $\Omega$cm at 50 W power and rf-bias voltage of -20 V. The best transmittance of ITO films at 550 nm wavelength is 91 % in the substrate power of 30 W and rf-bias voltage of -80 V.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.9-12
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• 2000

InP/lnGaAs heterojunciton phototransistors (HPTs) with transparent emitter contacts were fabricated and characterized. Indium Tin Oxide was RF sputtered for the emitter contacts. By comparison with InP/InGaAs HBTs, the dc characteristics of InP/lnGaAs HPTs demonstrated offset voltage due to ITO emitter contacts and similar common emitter current gain. The model parameters were extracted and a simple SPICE simulations were performed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.8
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• pp.49-55
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• 1992

We Have investigated the properties of the titanium nitrite films widely used in VLSI devices as diffusion barrier in Al-based metallization. TiN films were formed by reactive sputtering from Ti target in Ar-N$_2$ mixtures, varying deposition parameters such as N$_2$ partial pressure, substrate temperature, power, and total pressure. All the samples received the heat treatment at 45$0^{\circ}C$ for 30 min. The resulting films are characterized by mechanical stylus($\alpha$-step), x-ray diffraction(XRD), scanning electron microscopy(SEM), and four point probe method. The Tin film properties strongly depend on the deposition condition. The stoichiometry and Ti deposition rate are critically affected by nitrogen partial pressure, and the resistivity, in particular, is dependent on both the substrate temperature and sputtering power.