• Applied Science and Convergence Technology
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• 제26권2호
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• pp.26-29
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• 2017

Thin films of europium-doped yttrium oxide ($Y_2O_3$:Eu) were prepared on Si (100) substrates by using a radio frequency (RF) magnetron sputtering. After the deposition, the films were annealed at $1000^{\circ}C$ in an air ambient for 1 hour. X-ray diffraction analysis revealed that the $Y_2O_3$:Eu films had a polycrystalline cubic ${\alpha}-Y_2O_3$ structure. The as-deposited films showed no photoluminescence (PL), which was due to poor crystalline quality of the films. The crystallinity of the $Y_2O_3$:Eu films was significantly improved by annealing. The strong red PL emission was observed from the annealed $Y_2O_3$:Eu films and the highest intensity peak was centered at around 613 nm. This emission peak originated from the $^5D_0{\rightarrow}^7F_2$ transition of the trivalent Eu ions occupying the $C_2$ sites in the cubic ${\alpha}-Y_2O_3$ lattice. The broad PL excitation band was observed at wavelengths below 280 nm, which was attributed to the charge transfer transition of the trivalent Eu ion.

• 한국표면공학회지
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• 제49권3호
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• pp.225-230
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• 2016

The present work was conducted to investigate the effects of NaF concentration in phosphate and silicate-containing alkaline electrolyte on the morphology, thickness, surface roughness and hardness of anodic oxide films formed on AZ31 Mg alloy by plasma electrolytic oxidation (PEO) method. The PEO films showed flat surface morphology with pores in the absence of NaF in the electrolyte, but nodular features appeared on the PEO film surface prepared in NaF-containing electrolyte. Numerous pores ranging from 1 to $20{\mu}m$ in size were observed in the PEO films and the size of pores decreased with increasing NaF concentration in the electrolyte. Surface roughness and thickness of PEO films showed increases with increasing NaF concentration. Hardness of the PEO films also increased with increasing NaF concentration. It was noticed that hardness of inner part of the PEO films is lower than that of outer part of them, irrespective of the concentration of NaF. The low hardness of PEO films was explained by the presence of a number of small size pores less than $2{\mu}m$ near the PEO film/substrate interface.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.121-121
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• 2003

NiO thin films are very attractive for use as an antiferromagnetic layer, p-type transparent conducting films, in electrochromic devices and functional sensor layer for chemical sensors, due to their excellent chemical stability, as well as optical, electrical and magnetic properties. In addition, (100)- and (111)-oriented NiO films can be used as buffer layers on which to deposit other oriented oxide films, such as c-axis-oriented perovskite-type ferromagnetic films and superconducting films, because of the similarity in symmetry of oxygen ion lattice and lattice constants between the NiO films and the oriented oxide films. Thus, controlling the crystallographic orientation and surface roughness of the NiO films for a buffer layer are very important.

• 한국표면공학회지
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• 제42권6호
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• pp.267-271
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• 2009

Multicomponent transparent conducting oxide films were deposited on glass substrates at 150 by dual magnetron sputtering of AZO and ITO targets. In the case of mixing a limited amount of ITO (10W), resistivity of TCO films was significantly increased compared to the AZO film; from $3.5{\times}10^{-3}$ to $9.7{\times}10^{-3}{\Omega}{\cdot}cm$. Deterioration of the electrical conductivity is attributed to the decreases in carrier concentration and Hall mobility. Improvement of the conductivity could be obtained for the films prepared with ITO powers larger than 40 W. The lowest resistivity ($\rho$) of $7.3{\times}10^{-4}{\Omega}{\cdot}cm$ was achieved when ITO power was 100 W. Effects of $H_2$ incorporation on the electrical and optical properties of AZO-ITO films were investigated in this work. Addition of small amount of hydrogen resulted in the increase of carrier concentration and the improvement of electrical conductivity. It is apparent that the roughness of AZO-ITO films decreases dramatically after the transition of microstructure from polycrystalline to amorphous phase, which gives practical advantages such as an excellent uniformity of surface and a high etching rate. AZO-ITO films grown at sputtering ambient with hydrogen gas are expected to be applicable to optoelectronic devices such as organic light emitting diodes and flexible displays due to their sufficient electrical and structural properties.

• 한국세라믹학회지
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• 제41권1호
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• pp.57-61
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• 2004

Zinc Oxide (ZnO)은 wurtzite 결정구조를 가지고 있으며, 밴드갭 에너지가 약 3.3eV로 반도성 산화물이다. $In_2O_3$이 첨가된 ZnO 박막을 점자빔증착법을 이용하여 1737F 유리기판에 제조하였다. $400^{\circ}C$의 증착온도에서 $In_2O_3$의 첨가량에 따른 ZnO 박막의 결정성, 미세구조를 비롯한 전기.광학적 특성을 조사하였다. 첨가되는 $In_2O_3$의 양에 따라 투명전도성 산화막으로써의 ZnO 박막의 특성이 변화되었다. $In_2O_3$의 첨가량이 감소할수록 비정질상에서 결정성의 ZnO 막을 얻을 수 있었다. 0.2at%의 $In_2O_3$가 첨가된 출발물질에서 제조된 $In_2O_3$-doped ZnO막은 약 $6.0 {\times} 10^{-3} {\Omega}cm$ 정도의 비저항값과 가시광선 영역에서 85% 이상의 광투과도를 나타내었다.

• 한국전기전자재료학회논문지
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• 제25권7호
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• pp.543-551
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• 2012

In this study, transparent conducting Al-doped Zinc Oxide (AZO) films with a thickness of 150 nm were prepared on corning glass substrate by the RF magnetron sputtering with using a Al-doped zinc oxide (AZO), ($Al_2O_3$: 2 wt%) target at room temperature. This study investigated the effect of rapid thermal annealing temperature and oxygen ambient on structural, electrical and optical properties of Al-doped zinc oxide (AZO) thin films. The films were annealed at temperatures ranging from 400 to $700^{\circ}C$ by using Rapid thermal equipment in oxygen ambient. The effect of RTA treatment on the structural properties were studied by x-ray diffraction and atomic force microscopy. It is observed that the Al-doped zinc oxide (AZO) thin film annealed at $500^{\circ}C$ at 5 minute oxygen ambient gas reveals the strongest XRD emission intensity and narrowest full width at half maximum among the temperature studied. The enhanced UV emission from the film annealed at $500^{\circ}C$ at 5 minute oxygen ambient gas is attributed to the improved crystalline quality of Al-doped zinc oxide (AZO) thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.421.1-421.1
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• 2016

We studied indium-doped zinc oxide (IZO) film grown by atomic layer deposition (ALD) as transparent conductive oxide (TCO). A variety of TCO layer, such as ZnO:Al (AZO), InSnO2(ITO), Zn (O,S) etc, has been grown by various method, such as ALD, chemical vapor deposition (CVD), sputtering, laser ablation, sol-gel technique, etc. Among many deposition methods, ALD has various advantages such as uniformity of film thickness, film composition, conformality, and low temperature deposition, as compared with other techniques. In this study, we deposited indium-doped zinc oxide thin films using diethyl[bis(trimethylsilyl)amido]indium [Et2InN(TMS)2] as indium precursor, DEZn as zinc precursor and H2O as oxidant for ALD and investigated the optical and electrical properties of IZO films. As an alternative, this liquid In precursor would has several advantages in indium oxide thin-film processes by ALD, especially for low resistance indium oxide thin film and high deposition rate as compared to InCp, InCl3, TMIn precursors etc. We found out that Indium oxide films grown by Et2InN(TMS)2 and H2O precursor show ALD growth mode and ALD growth window. We also found out the different growth rate of Indium oxide as the substrate and investigated the effect of the substrate on Indium oxide growth.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.179-182
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• 1994

We have investigated the optical and electrochromic properties of molybdenum oxide(MoO$_3$) films by thermal evaporation. The MoO$_3$films deposited at substrate temperatures below 200$^{\circ}C$ are found to be amorphous and annealed films at temperature 300$^{\circ}C$ for 1 hour in air are crystalline. The optical energy gap calculated from the transmittance and reflectance spectra of MoO$_3$ films is near 2.75 eV and 3.25 eV for amorphous films and crystalline films, respectively. The MoO$_3$ thin films exhibit light blue to dark blue optical modulation on lithium intercalation and have a uniform transmittance modulation over a wavelength range of 300∼1100 nmcompared to tungsten oxide films.

• 한국표면공학회지
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• 제33권5호
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• pp.349-355
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• 2000

Indium tin oxide (ITO) thin films have been deposited on PET (polyethylene terephthalate) and glass substrates by a do magnetron sputter method of powder target without heat treatments such as substrate heater and post heat treatment. During the sputtering deposition, sputtering parameters such as sputtering power, working pressure, oxygen gas mixture, film thickness and substrate-target distance are important factors for the high quality of ITO thin films. The structural, electrical and optical properties of as-deposited ITO oxide films are investigated by sputtering power, oxygen partial pressure and films thickness among the several sputtering conditions. XRD patterns of ITO films are affected by sputtering power and pressure. As the power and pressure are increased, (411) and (422) peaks of ITO films are grown strongly. Electrical resistivity is also increased, as the sputtering power and pressure are increased. Transmittance of ITO thin films in the visible light ranges is lowered with an increase of sputtering power and film thickness. Reflectance of ITO films in infra-red region is decreased, as the power and pressure is increased.

• Carbon letters
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• 제14권4호
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• pp.247-250
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• 2013

In this study, we present a facile method of fabricating graphene oxide (GO) films on the surface of polyimide (PI) via layer-by-layer (LBL) assembly of charged GO. The positively charged amino-phenyl functionalized GO (APGO) is alternatively complexed with the negatively charged GO through an electrostatic LBL assembly process. Furthermore, we investigated the water vapor transmission rate and oxygen transmission rate of the prepared (reduced GO $[rGO]/rAPGO)_{10}$ deposited PI film (rGO/rAPGO/PI) and pure PI film. The water vapor transmission rate of the GO and APGO-coated PI composite film was increased due to the intrinsically hydrophilic property of the charged composite films. However, the oxygen transmission rate was decreased from 220 to 78 $cm^3/m^2{\cdot}day{\cdot}atm$, due to the barrier effect of the graphene films on the PI surface. Since the proposed method allows for large-scale production of graphene films, it is considered to have potential for utilization in various applications.