• 반도체디스플레이기술학회지
• /
• 제17권4호
• /
• pp.66-69
• /
• 2018

This study was researched the electrical properties of semiconductor devices such as ITO, $SiO_2$, $V_2O_5$ thin films. The films of ITO, $SiO_2$, $V_2O_5$ were deposited by the rf magnetron sputtering system with mixed gases of oxygen and argon to generate the plasma. All samples were cleaned before deposition and prepared the metal electrodes to research the current-voltage properties. The electrical characteristics of semiconductors depends on the interface's properties at the junction. There are two kinds of junctions such as ohmic and schottky contacts in the semiconductors. In this study, the ITO thin film was shown the ohmic contact properties as the linear current-voltage curves, and the electrical characteristics of $SiO_2$ and $V_2O_5$ films were shown the non-linear current-voltage curves as the schottky contacts. It was confirmed that the electronic system with schottky contacts enhanced the electronic flow owing to the increment of efficiency and increased the conductivity. The schottky contact was only defined special characteristics at the semiconductor and the interface depletion layer at the junction made the schottky contact which has the effect of leakage current cutoff. Consequently the semiconductor device with shottky contact increased the electronic current flow, in spite of depletion of carriers.

• Corrosion Science and Technology
• /
• 제20권4호
• /
• pp.204-209
• /
• 2021

Corrosion failure analysis of the flow plate, which is one of the accessories of the plate heat exchanger in a district heating system, was performed. The flow plate is made of 316 stainless steel, and water at different temperatures in the flow plate exchanges heat in a non-contact manner. The flow plate samples in which water mixing issues occurred were collected. Corrosion-induced pits, oxides, and contaminants were observed at locations where two plates are regularly in contact. The EDS analysis of the surface oxides and contaminants revealed that they were composed of carbon, silicon, and magnesium, which came from chemical adhesives. The IC/ICP analyses showed that the concentration of chloride ions was 30 ~ 40 ppm, which was not sufficient to cause corrosion of stainless steel. In the crevice, a local decrease in dissolved oxygen occurs along with an increase in chloride ions, thus forming an acidic environment. These environments destroyed the passive film of stainless steel, resulting in pits. Moreover, contaminants formed a narrower gap between the two metal plates and inhibited the diffusion of ions, thereby accelerating crevice corrosion.

• 융합정보논문지
• /
• 제11권2호
• /
• pp.10-15
• /
• 2021

본 논문에서는 먼저 습식 코팅 방법으로 페로브스카이트 (CH3NH3PbI3) 박막을 글라스 상에 형성하고, 다양한 분석 기법을 이용하여 막의 두께, 표면거칠기, 결정성, 구성성분 및 가시광 영역에서의 이 물질의 반응에 대해 논한다. 완성된 반도체 물질은 막내부에 결함(defect)이 없고 균일하며, 표면거칠기는 매우 작으며, 가시광영역에서 높은 흡수율이 관찰되었다. 다음으로 이와 같이 형성된 유무기 층에 hole 형상을 구현하기 위하여, 구멍이 일정한 간격으로 있는 메탈마스크, 페로브스카이트 물질이 코팅되어 있는 유리, 자석 순서로 되어있는 구조의 샘플을 상압플라즈마 공법을 이용하여 시간에 따른 물질에 형성되는 hole 형태의 변화를 분석하였다. 시간이 길어짐에 따라 더 많이 식각되는 것을 알 수 있으며, 이 중에서 공정 시간을 가장 오래한 샘플에 대해서는 보다 자세하게 살펴보았고, 플라즈마의 위치에 따른 차이에 의해 7영역으로 분류할 수 있었다.

• 대한금속재료학회지
• /
• 제49권10호
• /
• pp.811-817
• /
• 2011

In this study, we have investigated the role of a metal oxide hole injection layer (HIL) between an Indium Tin Oxide (ITO) electrode and an organic hole transporting layer (HTL) in organic light emitting diodes (OLEDs). Nickel Oxide films were deposited at different deposition times of 0 to 60 seconds, thus leading to a thickness from 0 to 15 nm on ITO/glass substrates. To study the influence of NiO film thickness on the properties of OLEDs, the relationships between NiO/ITO morphology and surface properties have been studied by UV-visible spectroscopy measurements and AFM microscopy. The dependences of the I-V-L properties on the thickness of the NiO layers were examined. Comparing these with devices without an NiO buffer layer, turn-on voltage and luminance have been obviously improved by using the NiO buffer layer with a thickness smaller than 10 nm in OLEDs. Moreover, the efficiency of the device ITO/NiO (< 5 nm)/NPB/$Alq_3$/ LiF/Al has increased two times at the same operation voltage (8V). Insertion of a thin NiO layer between the ITO and HTL enhances the hole injection, which can increase the device efficiency and decrease the turn-on voltage, while also decreasing the interface roughness.

• 한국산학기술학회논문지
• /
• 제22권1호
• /
• pp.562-567
• /
• 2021

다양한 건축시설 및 생활제품에 적용하기 위한 기능성 항균강화유리개발을 위해 국산 소재들의 항균력을 조사하여, 특정농도에서 99% 이상의 항균력을 갖는 은, 구리, 아연으로 강화유리 시편을 제작하였다. 은, 구리, 아연을 Ethylene glycol + Glycerol로 분산시킨 시편의 항균력은 모두 99% 이상으로 측정되었고, Ethylene glycol과 Glycerol을 단독으로 사용했을 때는 항균력이 감소되었다. 표면분석기를 사용하여 세척에 의한 결합된 금속소재의 두께 변화를 측정한 결과, 물을 포함한 다양한 종류의 세제로 세척한 시편에서는 표면에 도포된 소재의 두께가 1% 미만으로 감소하였지만, 염기성 세제에서는 약 10%의 표면두께 감소가 확인되었다. 또한, 시편의 인체 안전성을 확인하기 위해, MTT 분석법을 통한 세포독성실험을 수행하였고, 항균물질들이 도포된 시편에서의 세포독성은 대조군과 비교하였을 때 거의 나타나지 않았다. 마지막으로, 시제품의 항균력이 99% 이상임을 Bacterial Live/dead kit을 이용하여 확인하였고, 공인인증기관의 필름밀착법으로 다시 한 번 시제품의 항균력을 검증하였다. 결국, 본 연구에서는 국산소재들의 항균력을 검증과 함께 이를 이용한 고기능성 항균효과 갖는 강화유리를 개발하였다.

• 센서학회지
• /
• 제31권5호
• /
• pp.348-352
• /
• 2022

Hydrogen gas (H₂) which is odorless, colorless is attracting attention as a renewable energy source in varions applications but its leakage can lead to disastrous disasters, such as inflammable, explosive, and narcotic disasters at high concentrations. Therefore, it is necessary to develop H₂ gas sensor with high performance. In this paper, we confirmed that H₂ gas detection ability of SnO₂ based H₂ gas sensor along with thermal treatment effect of SnO₂. Proposed SnO₂ based H₂ gas sensor is fabricated by MEMS technologies such as photolithgraphy, sputtering and lift-off process, etc. Deposited SnO₂ thin films are thermally treated in various thermal treatement temperature in range of 500-900 ℃ and their H₂ gas detection ability is estimatied by measuring output current of H₂ gas sensor. Based on experimental results, fabricated H₂ gas sensor with SnO₂ thin film which is thermally treated at 700 ℃ has a superior H₂ gas detection ability, and it can be expected to utilize at the practical applications.

• 한국분말재료학회지
• /
• 제30권1호
• /
• pp.53-64
• /
• 2023

Atomic layer etching (ALE) is a promising technique with atomic-level thickness controllability and high selectivity based on self-limiting surface reactions. ALE is performed by sequential exposure of the film surface to reactants, which results in surface modification and release of volatile species. Among the various ALE methods, thermal ALE involves a thermally activated reaction by employing gas species to release the modified surface without using energetic species, such as accelerated ions and neutral beams. In this study, the basic principle and surface reaction mechanisms of thermal ALE?processes, including "fluorination-ligand exchange reaction", "conversion-etch reaction", "conversion-fluorination reaction", "oxidation-fluorination reaction", "oxidation-ligand exchange reaction", and "oxidation-conversion-fluorination reaction" are described. In addition, the reported thermal ALE processes for the removal of various oxides, metals, and nitrides are presented.

• 한국표면공학회지
• /
• 제56권4호
• /
• pp.233-242
• /
• 2023

In recent years, energy-management studies in buildings have proven useful for energy savings. Typically, during heating and cooling, the energy from a given building is lost through its windows. Generally, to block the entry of ultraviolet (UV) and infrared (IR) rays, thin films of deposited metals or metal oxides are used, and the blocking of UV and IR rays by these thin films depends on the materials deposited on them. Therefore, by controlling the thicknesses and densities of the thin films, improving the transmittance of visible light and the blocking of heat rays such as UV and IR may be possible. Such improvements can be realized not only by changing the two-dimensional thin films but also by altering the zero-dimensional (0-D) nanostructures deposited on the films. In this study, 0-D nanoparticles were synthesized using a sol -gel procedure. The synthesized nanoparticles were deposited as deep coatings on polymer and glass substrates. Through spectral analysis in the UV-visible (vis) region, thin-film layers of deposited zinc oxide nanoparticles blocked >95 % of UV rays. For high transmittance in the visible-light region and low transmittance in the IR and UV regions, hybrid multiple layers of silica nanoparticles, zinc oxide particles, and fluorine-doped tin oxide nanoparticles were formed on glass and polymer substrates. Spectrophotometry in the UV-vis-near-IR regions revealed that the substrates prevented heat loss well. The glass and polymer substrates achieved transmittance values of 80 % in the visible-light region, 50 % to 60 % in the IR region, and 90 % in the UV region.

• Journal of Electrochemical Science and Technology
• /
• 제13권2호
• /
• pp.237-253
• /
• 2022

The methyl 2-(1,3-dithietan -2- ylidene)-3-oxobutanoate (MDYO) and 2-(1,3-dithietan-2-ylidene) cyclohexane -1,3-dione (DYCD) were synthesized and tested at various concentrations as corrosion inhibitors for 316L stainless steel in 1 M HCl using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface analysis techniques (SEM / EDX and Raman spectroscopy) and Functional Density Theory (DFT) was also used to calculate quantum parameters. The obtained results indicated that the inhibition efficiency of MDYO and DYCD increases with their concentration, and the highest value of corrosion inhibition efficiency was determined in the range of concentrations investigated (0.01 × 10^-3 - 10^-3 M). Polarization curves (Tafel extrapolation) showed that both compounds act as mixed-type inhibitors in 1M HCl solutions. Electrochemical impedance spectra (Nyquist plots) are characterized by a capacitive loop observed at high frequencies, and another small inductive loop near low frequencies. The thermodynamic data of adsorption of the two compounds on the stainless steel surface and the activation energies were determined and then discussed. Analysis of experimental results shows that MDYO and DYCD inhibitors adsorb to the metal surface according to the Langmuir model and the mechanism of adsorption of both inhibitors involves physisorption. SEM-EDX results confirm the existence of an inhibitor protective film on the stainless steel surface. The results derived from theoretical calculations supported the experimental observation.

• 멤브레인
• /
• 제32권1호
• /
• pp.23-32
• /
• 2022

세균은 분리막, 식품 포장 필름 및 바이오 의료 기기와 같은 다양한 미생물 막의 표면 위에서 자란다. 미생물 막의 성장은 엑소폴리사카라이드의 복잡한 구조 형성과 밀접한 관련이 있다. 미생물 막이 항균제의 대량 수송의 어려움으로 성장하게 될 경우 항균효과는 급격하게 감소한다. 항균 활동을 활성화하기 위해서 막의 표면은 살균 특성이 있는 기능성 물질들로 변형, 코팅 또는 고정한다. 한 가지 아이디어는 막 표면에 양전하 이온을 도입하는 것이다. 양전하 이온인 4차 암모늄 그룹의 존재는 마그네슘이나 칼슘같이 세균 세포벽에 존재하는 2가 금속이온을 대체할 수 있다. 세포막 파괴의 효능은 표면환경에서 사용 가능한 작용제들의 이동성에 달려있다. 이 리뷰에서는 4차 암모늄 그룹, 헬라민(helamine), 쌍성이온(zwitterion)과 같이 여러 살생물제를 포함하고 있는 막들을 다룬다.