• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.65-65
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• 2011

Single-well carbon nanotubes (SWNT) have been proposed as a promising candidate for various applications owing to their excellent properties. In particular, their fascinating electrical and mechanical properties could provide a new area for the development of advanced engineering materials. A transparent conductive thin film (TCF) has increased for applications such as liquid crystal displays, touch panels, and flexible displays. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. But, a bundle of CNTs has different electrical properties than their individual counterparts. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodum dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate at $100^{\circ}C$. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then treated with ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. Results, we show that 97 ${\Omega}$/> sheet resistance can be achieved with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after ionic doping treatments were discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.347-347
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• 2012

Nickel Oxide (NiO) is a transition metal oxide of the rock salt structure that has a wide band gap of 3.5 eV. It has a variety of specialized applications due to its excellent chemical stability, optical, electrical and magnetic properties. In this study, we concentrated on the application of NiO thin film for transparent conducting oxide. The energy band structure, electronic and optical properties of Nickel Oxide (NiO) thin films grown on Si by using electron beam evaporation were investigated by X-Ray Photoelectron Spectroscopy (XPS), Reflection Electron Energy Loss Spectroscopy (REELS), and UV-Spectrometer. The band gap of NiO thin films determined by REELS spectra was 3.53 eV for the primary energies of 1.5 keV. The valence-band offset (VBO) of NiO thin films investigated by XPS was 3.88 eV and the conduction-band offset (CBO) was 1.59 eV. The UV-spectra analysis showed that the optical transmittance of the NiO thin film was 84% in the visible light region within an error of ${\pm}1%$ and the optical band gap for indirect band gap was 3.53 eV which is well agreement with estimated by REELS. The dielectric function was determined using the REELS spectra in conjunction with the Quantitative Analysis of Electron Energy Loss Spectra (QUEELS)-${\varepsilon}({\kappa},{\omega})$-REELS software. The Energy Loss Function (ELF) appeared at 4.8, 8.2, 22.5, 38.6, and 67.0 eV. The results are in good agreement with the previous study [1]. The transmission coefficient of NiO thin films calculated by QUEELS-REELS was 85% in the visible region, we confirmed that the optical transmittance values obtained with UV-Spectrometer is the same as that of estimated from QUEELS-${\varepsilon}({\kappa},{\omega})$-REELS within uncertainty. The inelastic mean free path (IMFP) estimated from QUEELS-${\varepsilon}({\kappa},{\omega})$-REELS is consistent with the IMFP values determined by the Tanuma-Powell Penn (TPP2M) formula [2]. Our results showed that the IMFP of NiO thin films was increased with increasing primary energies. The quantitative analysis of REELS provides us with a straightforward way to determine the electronic and optical properties of transparent thin film materials.

• Korean Journal of Materials Research
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• v.3 no.6
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• pp.632-637
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• 1993

The optical properties and electrochromism of amorphous $WO_3$ thin films were studied. $WO_3$ thin films with thickness of 3000$\AA$~6000$\AA$ were deposited by vacuum evaporat.ion. All these films were transparent and found to be amorphous in structure by X-ray diffraction analysis and the visible wave length refractive indices were found to be between 1.9 and 2.1 and the optical energey gap to be 3.25 eV. Electrochromic devices were made consisting of IT0 transparent electrode, $WO_3$ thin films, $LiCIO_4$- propylene carbonate and Pt counter electrode. In terms of their operation, the amorphous $WO_3$ films were colored blue by a double injection of electrons from the transparent electrode and lithium ions from the $LiCIO_4$-propylene carbonate organic electrolyte and made colorless by electrochemical oxidation reaction. The electrochromic properties of $WO_3$ thin films including coloration and bleaching, optical density and response time were all found to be strongly dependent on the film deposition condition, electrolyte concentration, sheet resistance of the transparent electrode and applied voltage.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.568-571
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• 2005

Highly transparent ZnO films with low resistivity for thin film solar cell applications were fabricated at low temperature by rf magnetron sputtering. Al-doped ZnO films were deposited on glass substrates at a substrate temperature of $200^{\circ}C$. electrical and optical properties of the ZnO:Al films were investigated in terms of the reparation conditions. The transmittance of the ZnO:Al films in the visible range is 90 %. The lowest resistivity of the ZnO:Al films is about $5.7\times10^{-4}$ $\Omega$ cm at the Al content of 2.5 wt% with the film thickness of 500 nm. After deposition, the smooth surface of ZnO:Al films were etched in diluted HCl (0.5%) to investigate the variation of electrical and surface morphology properties due to an textured surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.837-843
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• 2009

$TiO_2$(2 wt.%)-doped ZnO(TZO) films with thickness from 100 nm to 500 nm were prepared on polyethylene naphthalate(PEN) substrate under various rf-power range from 40 W to 80 W. Their electrical and optical properties were investigated as a function of rf-power. We think that these properties were closely related with the crystallization and the film density of TZO films. It was also presumed that the vaporization of the water vapor and other adsorbed particles such as an organic solvents can affect the electrical properties of the conventional transparent conductive oxide(TCO) films. On the other hand, since the TZO film deposited on glass substrate at room temperature with rf-power of 80 W shows a very low resistivity of $7.5\times10^{-4}\;\Omega{\cdot}cm$ and a very excellent transmittance over an average 85% in the visible range, that is comparable to that of ITO films. Therefore, we expect that the TZO films can be used as transparent electrode for optoelectronic devices such as touch-panels, flat-panel displays, and thin-film solar cells.

• Korean Journal of Materials Research
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• v.27 no.12
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• pp.695-698
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• 2017

ZnMgBeGaO/Ag/ZnMgBeGaO multilayer structures were sputter grown and characterized in detail. Results indicated that the electrical properties of the ZnMgBeGaO films were significantly improved by inserting an Ag layer with proper thickness (~ 10 nm). Structures with thicker Ag films showed much lower optical transmission, although the electrical conductivity was further improved. It was also observed that the electrical properties of the multilayer structure were sizably improved by annealing in vacuum (~35 % at $300^{\circ}C$). The optimum ZnMgBeGaO(20nm)/Ag(10nm)/ZnMgBeGaO(20nm) structure exhibited an electrical resistivity of ${\sim}2.6{\times}10^{-5}{\Omega}cm$ (after annealing), energy bandgap of ~3.75 eV, and optical transmittance of 65 % ~ 95 % over the visible wavelength range, representing a significant improvement in characteristics versus previously reported transparent conductive materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.242-248
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• 2008

The structural, optical and electrical properties of ZnO films doped with 1.5 at% of 3A materials(B, Al, Ga, In) were studied by sol-gel process. The films were found to be c-axis (002) oriented hexagonal structure on glass substrate, when post heated at 500 $^{\circ}C$. The surface of the films showed a uniform and nano size microstructure and the crystalline size of doped films decreased. The lattice constants of ZnO:B/Al/Ga increased than that of ZnO, while ZnO:In decreased. All the films were highly transparent(above 90 %) in the visible region. The energy gaps of ZnO:B/Al/Ga were increased a little, but that of ZnO:In was not changed. The resistivities of ZnO:Al/Ga/In were less than 0.1 $\Omega$cm. All the films showed a semiconductor properties in the light or temperature, however ZnO:In was less sensitive to it. A figure of merit of ZnO:In had the highest value of 0.025 $\Omega^{-1}$ in all samples.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.218-219
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• 2002

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.174-180
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• 2019

In this study, we evaluated and analyzed the properties of polymeric transparent films used in military vehicle covers according to weathering test. Two types of polymer films (Film A and Film B) that are mostly used for military vehicle covers were selected. The weathering treatment condition and tester are described in KS K 0706, and the following weathering times were tested: 0hour, 40hours, 160hours and 320 hours. The tensile strength, elongation and thermal decomposition behavior and optical characteristics were analyzed. The tensile strength tended to decrease - increase - decrease with increasing weathering treatment time in both transparent films. The thermal decomposition temperature gradually decreased. Regarding the optical property, the light transmittance decreased and the haze tended to increase. However, film A showed almost similar optical characteristics after 160-hour weathering treatment.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.234-234
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• 2003

Indium tin oxide(ITO) is an advanced ceramic material with many electronic and optical applications due to its high electrical conductivity and transparency to light ITO thin films are used in transparent electrodes for display devices, transparent coatings for solar energy heat mirrors and windows films in n-p heterojunction solar cells, etc. Almost all display devices were fabricated on transparent ITO electrode substrates. There are several factors that cause decay in the efficiency and the failure of display devices. The degradation or damage of ITO is one of the main factors. Under normal operating conditions, the electric fold required for the operation of display devices is very high As a high electric field induces the joule heat, the degradation of the ITO thin film may be expected. Therefore, it is worthy to investigate the thermal and electrical effect on ITO thin films.