• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.207.2-207.2
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• 2013

Oxide-based thin film transistors have been attempted as powerful candidates for driving circuits for active-matrix organic light-emitting diodes and transparent electronics. The oxide TFTs are based on the amorphous multi-component oxides involving zinc, indium, and/or tin elements as main cation sources. The current work employed RF sputtering in order to deposit zinc-tin oxide thin films applicable to transparent oxide thin film transistors. The deposited thin film was characterized and probed in terms of materials and devices. The physical/chemical characterizations were performed using X-ray diffraction, Atomic Force Microscopy, Spectroscopic Ellipsometry, and X-ray Photoelectron Spectroscopy. The thin film transistors were fabricated using a bottom-gated structure where thermally-grown silicon oxide layers were applied as gate-dielectric materials. The inherent properties of oxide thin films are combined with the corresponding device performances with the aim to fabricating the multi-component oxide thin films being optimized towards transparent electronics.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.324-324
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• 2012

투명전도체(Transparent Conducting Oxides: TCOs)는 일반적으로 면저항이 $103{\Omega}/sq$ 이하로 전기가 잘 통하며, 가시광선영역인 380~780 nm에서의 투과율이 80% 이상이고, 3.2eV 이상의 밴드갭을 가지는 재료로써, 전기전도도와 가시광선영역에서 투과성이 높아 전기적, 광학적 재료로 관심을 받아 다년간 연구대상이 되어오고 있다. 현재 가장 널리 사용되고 있는 투명전도체(Transparent Conducting Oxides: TCOs) 소재로는 Indium Tin Oxide (ITO)가 가장 각광받고 있지만, Indium의 가격상승과 박막의 열처리를 통해 저항이 증가하는 단점을 가지고 있어 이를 대체 할 새로운 소재 개발이 필요한 상황이다. 그러므로 투명전도체 소재 개발에 있어서 가장 중요한 연구과제는 Indium Tin Oxide(ITO)의 단점을 개선시키고 안정된 고농도의 In-Zn-Sn-O(ITZO) 박막을 성장시키는 것이다. 본 연구에서는 RF스퍼터링법에 의하여 Si wafer에 In-Zn-Sn-O(IZTO)를 $350{\AA}$ 만큼 증착시키고, 1시간 동안 $300^{\circ}C$, $350^{\circ}C$, $400^{\circ}C$로 각각 열처리 하였다. 박막의 전자적, 광학적 특성은 XPS(X-ray Photoelectron Spectroscopy), REELS(Reflection Electron Energy Loss Spectroscopy)를 이용하여 연구하였다. XPS측정결과, ITZO박막은 In-O, Sn-O and Zn-O의 결합을 가지고 있고, 박막의 열처리를 통해 $400^{\circ}C$에서 Zn2p의 피크가 가장 크게 나타나는 반면 In3d와 Sn3d는 열처리를 했을 때가 Room Temperature에서 보다 피크가 작아지는 것을 확인하였다. 이는 $400^{\circ}C$에서 Zn가 표면에 편석됨을 나타낸다. 그리고 REELS를 이용해 Ep=1500 eV에서의 밴드갭을 얻어보면, 밴드갭은 $3.25{\pm}0.05eV$로 온도에 크게 변화하지 않았다. 또한 QUEELS -Simulation에 의한 광학적 특성 분석 결과, 가시광선영역인 380nm~780nm에서의 투과율이 83%이상으로 투명전자소자로의 응용이 가능하다는 것을 보여주었다.

• 한국분말재료학회지
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• 제21권2호
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• pp.142-146
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• 2014

Fundamental experiences have been studied for development of pre-treatment process of Sn by-products such as solders. Dry and wet separation/recovery processes were considered by the differences of physical properties. The by-products, which are analyzed by solder metal and oxides. The metal and oxide were simply separated by dry ball-milling process for 12 hours, after that recovery metal powder might be reusable as lead or lead-free solders. In terms of wet separation process, samples were dissolved in $HNO_3+H_2O_2$ and the precipitation were analyzed by $SnO_2$. Overall efficiency of recovery might be increasing via developing simple pre-treatment process.

• Applied Science and Convergence Technology
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• 제24권2호
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• pp.41-46
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• 2015

Transparent conductive oxides (TCOs) are essential material in optoelectronics such as solar cells, touch screens and light emitting diodes. Particularly TCOs are attractive material for infrared cut off film due to their high transparency in the visible wavelength range and high infrared reflectivity. Among the TCO, Indium tin oxide has been widely used because of the high electrical conductivity and transparency in the visible wavelength region. But ITO has several limitations; expensive and low environmental stability. On the other hands, fluorine doped tin oxide (FTO) is well known for low cost, weather ability and stable in acidic and hydrogen. In this study, two different magnetron sputtering techniques with RF and DC modes at room temperature deposition of FTO thin film was conducted. The change of oxygen content is influence on the topography, transmittance and refractive index.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.367-367
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• 2013

Commercial applications of indium tin oxide (ITO) can be separated into two useful areas. As it is perceived to bear electrical properties and optical transparency at once, its chance to apply to promising fields, usually for an optical device, gets greater in the passing time. ITO is one of the transparent conducting oxides (TCO), and required to carry the relative resistance less than $10^{-3}{\Omega}$/cm and transmittances over 80 % in the visible wavelength of light. Because ITO has considerable refractive index, there exist applications for anti-reflection coatings. Anti-reflection properties require gradual change in refractive index from films to air. Such changes are obtained from film density or nano-clustered fractional void. Glancing angle deposition (GLAD) method is a well known process for adjusting nanostructure of the films. From its shadowing effects, GLAD helps to deposit well-controlled porous films effectively. In this study, we are comparing the reference sample to samples coated with controlled ITO multilayer accumulated by an e-beam evaporation system. At first, the single ITO layer samples are prepared to decide refractive index with ellipsometry. Afterwards, ITO multilayer samples are fabricated and fitted by multilayer ellipsometric model based on single layer data. The structural properties were measured by using atomic force microscopy (AFM), and by scanning X-ray diffraction (XRD) measurements. The ellipsometry was used to determine refractive indices and extinction coefficient. The optical transmittance of the film was investigated by using an ultraviolet-visible (UV-Vis) spectrophotometer.

• 한국재료학회지
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• 제20권11호
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• pp.611-616
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• 2010

A cobalt oxide - tin oxide nanocomposite based gas sensor on an $SiO_2$ substrate was fabricated. Granular thin film of tin oxide was formed by a rheotaxial growth and thermal oxidation method using dc magnetron sputtering of Sn. Nano particles of cobalt oxide were spin-coated on the tin oxide. The cobalt oxide nanoparticles were synthesized by polymer-assisted deposition method, which is a simple cost-effective versatile synthesis method for various metal oxides. The thickness of the film can be controlled over a wide range of thicknesses. The composite structures thus formed were characterized in terms of morphology and gas sensing properties for reduction gas of $H_2$. The composites showed a highest response of 240% at $250^{\circ}C$ upon exposure to 4% $H_2$. This response is higher than those observed in pure $SnO_2$ (90%) and $Co_3O_4$ (70%) thin films. The improved response with the composite structure may be related to the additional formation of electrically active defects at the interfaces. The composite sensor shows a very fast response and good reproducibility.

• 한국결정성장학회지
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• 제26권3호
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• pp.95-100
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• 2016

본 연구에서는 염화주석, 하이드라진 그리고 수산화나트륨을 원료로 하여 용액환원침전법과 수열반응법을 이용하여 주석산화물 결정을 제조하여, 주요 실험 변수에 의한 결정상 및 형상을 XRD와 SEM을 이용하여 분석하였다. 원료의 몰 비에 따라 구형 및 판상의 주석산화물 결정을 얻을 수 있었으며, 그 결정상은 SnO, $Sn_6O_4(OH)_4$이었다. 그리고 수열반응법에 의하여 얻어진 결정 모양은 온도 조건에 따라 판상 및 꽃 모양의 SnO 결정이 얻어졌다.

• 한국분말재료학회지
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• 제9권1호
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• pp.38-42
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• 2002

Effects of chemical compositions on the sintering behavior of the lead borosilicate glass developed for barrier ribs of plasma display panels were investigated in this study. Formation of pores during sintering of the glass was noted and their formation mechanism was investigated using XPS, TG/DTA, and XRD. The results indicated that pores are formed by the oxygen released from Pb-oxides during sintering.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.168-168
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• 2010

Transparent conduction oxides (TCOs) films is extensively reported for optoelectronic devices application such as touch panels, solar cells, liquid crystal displays (LCDs), and organic light emitting diodes(OLEDs). Among the many TCO film, indium tin oxide(ITO) is in great demand due to the growth of flat panel display industry. However, indium is not only high cost but also its deposits dwindling. Therefore, many studies are being done on the transparent conductive oxides(TCOs). We fabricated a target of IZTO(In2O3:ZnO:SnO2=70:15:15 wt.%) reduced indium. Then, IZTO thin films were deposited on glass substrates by pulsed DC magnetron sputtering with various oxygen flow ratio. The substrate temperature was fixed at the room temperature. We investigated the electrical, optical, structural properties of IZTO thin films. The electrical properties of IZTO thin films were dependent on the oxygen partial pressure. As a result, the most excellent properties of IZTO thin films were obtained at the 3% of oxygen flow rate with the low resistivity of $7.236{\times}10^{-4}{\Omega}cm$. And also the optical properties of IZTO thin films were shown the good transmittance over 80%. These IZTO thin films were used to fabricated organic light emitting diodes(OLEDs) as anode and the device performances studied. The OLED with an IZTO anode deposited at optimized deposition condition showed good brightness properties. Therefore, IZTO has utility value of TCO electrode although it reduced indium and we expect it is possible for the IZTO to apply to flexible display due to the low processing temperature.

• Tribology and Lubricants
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• 제32권3호
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• pp.88-94
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• 2016

We conduct a series of fretting corrosion tests on tin-coated electric contact to evaluate the effects of lubricant on fretting corrosion behavior. We perform these tests with a constant contact force at 25℃ 50℃, 75°C, and 100℃. In the tests with a span amplitude of 30 μm, we could not determine the conventional behavior of the first, second, and third stages of the change in electric resistance during fretting corrosion and observed that the contact resistance continuously increases with the cycles. This behavior is due to the fact that the generation of oxides on the tin-coated contact is controlled and stabilized by the presence of lubricant. SEM observations on samples with a span amplitude of 77 μm at all testing temperatures confirm that there is less oxide debris on the fretting damaged surface. Hence, for tin-coated electric connector, the effect of lubrication on the lifetime of the electric contact increases as the fretting span decreases and testing temperature increases, compared to those for connector without lubricant. Especially, for a specimen with a span amplitude of 30 μm at 100℃, the increment in contact lifetime due to lubricant is found to be more than 20 times, compared to that without lubricant.