• Journal of Magnetics
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• 제4권2호
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• pp.69-72
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• 1999

Magnetic properties and crystallographic structure of e-beam evaporated Co/Cr and Co/Mo multilayer thin films were investigated using VSM and XRD. Co/Cr and Co/Mo multilayer thin films are confirmed as an alternating layered structure. The structure of films with thicker Co layers than Cr and Mo layers are found to be a hcp structure with the c-axis perpendicular to the film plane. The direction of the film plane is the easy magnetization one. There is a no significant difference in shape of hysteresis loops between Co/Cr and Co/Mo multilayer films. It is found that Mo layer is more effective than Cr for preparing Co layer with c-axis normal to the film plane.

• 한국전기전자재료학회논문지
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• 제36권6호
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• pp.588-593
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• 2023

The advantage of OTFT technology is that large-area circuits can be manufactured on flexible substrates using a low-cost solution process such as inkjet printing. Compared to silicon-based inorganic semiconductor processes, the process temperature is lower and the process time is shorter, so it can be widely applied to fields that do not require high electron mobility. Materials that have utility as electrode materials include carbon that can be solution-processed, transparent carbon thin films, and metallic nanoparticles, etc. are being studied. Recently, a technology has been developed to facilitate charge injection by coating the surface of the Al electrode with solution-processable titanium oxide (TiOx), which can greatly improve the performance of OTFT. In order to commercialize OTFT technology, an appropriate method is to use a complementary circuit with excellent reliability and stability. For this, insulators and channel semiconductors using organic materials must have stability in the air. In this study, carbon-doped Mo (MoC) thin films were fabricated with different graphite target power densities via unbalanced magnetron sputtering (UBM). The influence of graphite target power density on the structural, surface area, physical, and electrical properties of MoC films was investigated. MoC thin films deposited by the unbalanced magnetron sputtering method exhibited a smooth and uniform surface. However, as the graphite target power density increased, the rms surface roughness of the MoC film increased, and the hardness and elastic modulus of the MoC thin film increased. Additionally, as the graphite target power density increased, the resistivity value of the MoC film increased. In the performance of an organic thin film transistor using a MoC gate electrode, the carrier mobility, threshold voltage, and drain current on/off ratio (I_on/I_off) showed 0.15 cm²/V·s, -5.6 V, and 7.5×10⁴, respectively.

• 한국전기전자재료학회논문지
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• 제30권1호
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• pp.23-26
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• 2017

Mo doped carbon (C:Mo) thin films were fabricated with various Mo target power densities by unbalanced magnetron sputtering (UBM). The effects of target power density on the surface, structural, and electrical properties of C:Mo films were investigated. UBM sputtered C:Mo thin films exhibited smooth and uniform surfaces. However, the rms surface roughness of C:Mo films were increased with the increase of target power density. Also, the resistivity value of C:Mo film as electrical properties was decreased with the increase of target power density. From the performance of organic thin filml transistor using conductive C:Mo gate electrode, the carrier mobility, threshold voltage, and on/off ratio of drain current (Ion/Ioff) showed $0.16cm^2/V{\cdot}s$, -6.0 V, and $7.7{\times}10^4$, respectively.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.145-146
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• 2002

Tribological properties of co-sputtered Molybdenum disulfide $(MoS_2)/Carbon\;(C)$ films were studied and compared with those of sputtered $MoS_2$ films. Friction tests were carried out using pin-on-disk friction testers to evluated their friction and wear behaviors in a vacuum ($10^{-5}Pa$), air and humid air of 30, 50, 80% RH. $MoS_2/C$ (14%) composite films exhibited about 9 times longer wear life in a vacuum and about 6 times longer wear life in dry air than $MoS_2$ films did. They also showed stable low friction coefficient of about 0.02 in a vacuum. In humid air, however, $MoS_2/C$ composite films hardly showed good tribological properties.

• Tribology and Lubricants
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• 제12권1호
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• pp.15-21
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• 1996

Friction and wear properties of MoS$_2$ bonded films were studied using the Falex testing machine, and their properties were evaluated in terms of the life and the load carrying capacity of the films. MoS$_2$ bonded films were formulated from the mixtures of MoS$_2$ solid particles and epoxyphenol resin, and they were applied onto AISI 4130 steel surface by dipping method to form lubricating bonded films. The results of the life and the load carrying capacity of the films showed that films were mainly affected by the surface temperature arisen from the frictional heat at the contact surface. To obtain enhanced tribological properties of the films, various combinations of solid lubricants and additives with a basic polymer resin were attempted and evaluated. The effects of surface pretreatment, such as sand blast or Zn-phosphating, were also investigated.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.232-241
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• 1997

The tribological behavior for MoS$_2$ bonded films is evaluated according to the international standard testing methods, such as ASTM D 2625(Falex tester) and ASTM D 2714(LFW-1 tester). It has been well known that the tribological behavior for MoS$_2$ bonded films is affected by several factors. However, in this work, the wear life for MoS$_2$ bonded films is mainly experimentally measured with different contact geometry, and evaluated in terms of the frictional heating according to the contact geometry of tribotester. The test results show that the wear life of MoS$_2$ bonded films is significantly affected not only by the frictional heating, but also by the contact pressure, test running-in conditions, and the contact conformity.

• Tribology and Lubricants
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• 제13권3호
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• pp.20-27
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• 1997

The tribological behavior for $MoS_2$ bonded films is evaluated according to the international standard testing methods, such as ASTM D 2625 (Falex tester) and ASTM D 2714 (LFW1 tester). It has been well known that the tribological behavior for $MoS_2$ bonded films is affected by several factors. However, in this work, the wear life for $MoS_2$ bonded films is mainly experimentally measured with different contact geometry, and evaluated in terms of the frictional heating according to the contact geometry of tribotester. The test results show that the wear life of $MoS_2$ bonded films is significantly affected not only by the frictional heating, but also by the contact pressure, test running-in conditions, and the contact conformity.

• 대한화학회지
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• 제41권5호
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• pp.223-233
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• 1997

초고진공조에서 산소 분압, $1{\times}10^{-6}$ Torr, 하에서 Ti 금속을 Mo(100)에 증발시킴으로써 $TiO_2$ 초박막을 성장시켰다. Ti 금속을 Mo(100) 표면에 증착시킨 시간에 따른 오재(Auger) 봉우리의 크기 변화율을 조사함으로써 Ti 금속의 증발 속도를 알아내고, 그것을 이용하여 $TiO_2$ 박막 성장시 박막의 두께를 조절하였다. 30 ML, 5 ML, 1.6 ML 두께의 $TiO_2$ 박막을 만들어 박막의 성장메카니즘, 박막의 화학적 조성, 박막의 표면 구조를 연구하였다. 박막의 성장 메커니즘은 층별 성장에 가까운 성장 방식인 것으로 설명할 수 있다. 박막의 화학적 조성은 본체 $TiO_2$ 와 동일하였다. 박막의 표면은 (001) 평면이며, 고온 1200 K에서 비가역적으로 부면화(faceging)한다. 박막으로부터 관찰된 저에너지 전자회절 무늬는 $TiO_2$ (001) 표면이 {011} 평면을 가진 부면을 형성하고 각 부면이 다시 $TiO_2$ (001) 평면에 대하여 $(2\sqrt2{\times}\sqrt2)R45^{\circ}$로 재건축한다는 것으로 설명될 수 있다. 박막은 1300 K의 고온에서 얼마간 열적 불안정성을 보인다. $Ar^+$ 이온으로 스퍼터링한 $TiO_2$ 박막에 대하여 XPS를 이용하여 역시 알아보았다.

• Corrosion Science and Technology
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• 제9권1호
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• pp.20-28
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• 2010

According to the bipolar model, ion selectivity of some species in the passive film is important factor to control the passivation. An increase of cation selectivity of outer layer of the passive film can stabilize the film and improves the corrosion resistance. Therefore, the formation and roles of ionic species in the passive film should be elucidated. In this work, two types of solution (hydrochloric or sulfuric acid) were used to test high N and Mo-bearing stainless steels. The objective of this work was to investigate the formation of oxyanions in the passive film and the roles of oxyanions in passivation of stainless steel. Nitrogen exists as atomic nitrogen, nitric oxide, nitro-oxyanions (${NO_x}^-$), and N-H species, not nitride in the passive film. Because of its high mobility, the enriched atomic nitrogen can act as a reservoir. The formation of N-H species buffers the film pH and facilitates the formation of oxyanions in the film. ${NO_x}^-$ species improve the cation selectivity of the film, increasing the oxide content and film density. ${NO_x}^-$ acts similar to a strong inhibitor both in the passive film and at active sites. This facilitates the formation of chromium oxide. Also, ${NO_x}^-$ can make more molybdate and nitric oxide by reacting with Mo. The role of Mo addition on the passivation characteristics of stainless steel may differ with the test environment. Mo exists as metallic molybdenum, molybdenum oxide, and molybdate and the latter facilitates the oxide formation. When nitrogen and molybdenum coexist in stainless steel, corrosion resistance in chloride solutions is drastically increased. This synergistic effect of N and Mo in a chloride solution is mainly due to the formation of nitro-oxyanions and molybdate ion. Oxyanions can be formed by a 'solid state reaction' in the passive film, resulting in the formation of more molybdate and nitric oxide. These oxyanions improve the cation selectivity of the outer layer and form more oxide and increase the amount of chromium oxide and the ratio of $Cr_2O_3/Cr(OH)_3$ and make the film stable and dense.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 춘계학술대회
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• pp.122-127
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• 1996

In this paper, the effects of the film tinckness, pre-treatment and testing load on. the tribological characteristics have been studied. During the "Ring on-Disk" testing period silica-gel was used to remove the effect of humidity. As a result, increasing the film thickness revealed prolonged wear life, in the case or reasl the testing loads the dynamic friction coefficient was decreased gradually but in regarding the wear life, an intermideate contact pressure (4kgf/mm${2}$) revealed the maximum value. In regarding the surface protuberance friction an intermediate value of area fraction (60%) revealed maximum wear life. In this paper, the qualitative model in regarding the variation of the friction coefficient andworn depth was presented.presented.