• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.173-176
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• 1997

The III-V nitride semiconductor InN thin films which have the direct bandgap in visible light wavelength region have been deposited on Si(100) substrates and AIN/Si(100) substrates by rf reactive sputtering. InN thin films have been investigated on the structural, and electrical properties according to the sputtering parameters such as total pressure, rf power, and substrate temperature. It is found that optimal conditions required for fabricating InN thin films with high crystal Quality, low carrier concentration, high Hall mobility are total pressure 5mTorr, rf power 60W, substrate temperature 6$0^{\circ}C$ . InN thin films deposited on the AIN(60min.)/Si(100) substrates arid AIN(120min.)/Si(100) substrates showed remarkably high crystal quality and electrical properties. It is known that AIN buffer layer is to decrease free energy at interface between InN film and Si substrate, and then promoting lateral growth of InN films.

• 열처리공학회지
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• 제14권3호
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• pp.151-154
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• 2001

$TiO_2$ thin film has wide application because of its high capacitanca, reflection, and good transmissivity in visible range. $TiO_2$ thin film can be made by thermal deposition method, reactive evaporation method, activated reactive evaporation(ARE) method. In the case of thermal deposition, the oxygen deficiency can occur because the melting point of Ti is very high. While in the case of reactive evaporation, high density $TiO_2$ can not be made, because reactive gas($O_2$) and evaporated material(Ti) are not fully combined, activated reactive evaporation, $TiO_2$ is easily deposited at lower gas pressure compared with reactive evaporation because the ionized reactive gas is made by plasma. Therefore, activated reactive evaporation is very useful to deposit the material having the high melting point. In this work, we formed $TiO_2$ thin film by activated reactive evaporation method. The surface of $TiO_2$ thin film was analyzed by X-ray photoelectron spectroscopy. The surface morphology which was analyzed by atomic force microscopy(AFM) shows that feature of the film surface is uniform. The dielectric capacitance, withstanding voltage were $600{\mu}F/cm^2$, 0.4V respectively. In further work, we can increase the withstanding voltage by improving the deposition parameter of substrates.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.459-459
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• 2011

Graphene has many fascinating material properties such as high electron mobility, high optical transparency, excellent thermal conductivity, superior Young's modulus, etc. Several studies have recently found that single-layer graphene is chemically more reactive than few-layer graphene when supported on silicon dioxide substrates with sub-nm roughness. In this study, we have investigated the influence of substrates on chemical reactivity of graphene. Morphology and thermal oxidation behavior of graphene on atomically flat mica substrates were studied by atomic force microscopy (AFM) and Raman spectroscopy compared to graphene on SiO2/Si substrates. Notably, oxidation of single-layer graphene proceeds more slowly on mica than SiO2/Si. Detailed analysis led to a conclusion that deformation along the out-of-plane direction enhances reactivity of graphene.

• Journal of the Korean Wood Science and Technology
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• 제32권1호
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• pp.28-34
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• 2004

본 연구는 자기가수분해전 처리를 통하여 제조한 반응성이 높은 셀룰로오스(high reactive cellulose, HRC)기질의 카르복시메틸화(carboxymethylation, CM화) 특성을 알기 위하여 수행되었으며, 비교를 위하여 시판 알파셀룰로오스(commercial α-cellulose, CAC) 및 침엽수 리파이나기계펄프(Refiner mechanical pulp, RMP) 2종의 시료를 사용하였다. HRC는 12시간 당화처리로 70%, 24시간 처리로 90%, 72시간 처리로 99.5%의 높은 당화율을 나타냈다. 아울러 Cellulase 효소활성에 있어서 처리 전후에 측정된 CMCase 및 Avicelase의 효소활성의 큰 변화가 없었다. 이에 대하여 72시간 처리로 CAC는 57%의 당화율을, 리그닌을 많이 포함하는 RMP는 38%의 매우 낮은 당화율을 보였다. CM화시 리그닌함량이 낮은 HRC 및 CAC시료의 CM화가 용이하였고, 1.13-1.15의 높은 치환도를, 리그닌함량이 많은 RMP는 0.85 정도의 낮은 치환도를 나타냈다. 모든 시료에서 알칼리의 농도는 30%, 3시간 처리가 가장 높은 치환도를 보여주었다. CM화물로부터의 수용성부분은 HRC 및 CAC에서 98-98.5%, RMP 로부터는 31.5%로 매우 낮았다. 비표면적이 낮은 RMP는 보수도가 매우 낮았으며, 비표면적이 높았던 CAC 및 HRC는 435% 및 321%의 매우 높은 보수도 값을 나타냈다. 팽윤도에 있어서는 비표면적과는 무관하게 HRC, RMP 그리고 CAC 순으로 팽윤율이 커졌다.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.846-851
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• 2004

Transparent conducting indium tin oxide (TC-ITO) thin films on polymeric substrates have been deposited by a dc reactive magnetron sputtering without heat treatments. The polymeric substrates are acryl (AC), poly carbornate (PC), and polyethlene terephthalate (PET) as well as soda lime glass is also used to compare with the polymeric substrates. Sputtering parameters are an important factor for high quality of TC-ITO thin films prepared on polymeric substrates. Furthermore, the material, electrical and optical properties of as-deposited ITO films are dominated by the ratio of oxygen partial pressure. As the experimental results, the surface roughness of ITO films becomes rough as the oxygen partial pressure increases. The electrical resistivity of as-deposited ITO films decreases initially, and then increases with the increase of oxygen partial pressure. The optical transmittance at visible wavelength for all polymeric substrates is above 82 %.

• Transactions on Electrical and Electronic Materials
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• 제1권2호
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• pp.23-27
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• 2000

Indium in oxide(ITO) films have been deposited on PET and glass substrates by DC reactive magnetron sputtering without post-deposition thermal treatment, The high quality for microstructure, electrical and optical properties of the as-deposited ITO films on unheated substrates is dominated by the sputtering parameters, The influence of the working gas pressure, DC power and oxygen partial pressure has been systematically investigated, The lowest DC power, and oxygen partial pressure has been systematically investigated, The lowest resistivity of ITO films deposited on PET substrates was 6$\times$10$^{-4}$ $\Omega$cm. It has been obtained at a working pressure of 3 mTorr and DC power of 30 W. The sheet resistance and optical transmittance of these film were 22 $\Omega$/square and 84% respectively. The best values of figures of merit for the electrical and optical characteristics such as T/ $R_{sh}$ and $T^{10}$ / $R_{sh}$ are approximately 38.1 and 7.95($\times$10$^{-3}$ $\Omega$$^{-1}$ ), respectively.

• 한국표면공학회지
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• 제29권5호
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• pp.498-504
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• 1996

The synthesis of carbon nitride thin films with high nitrgen concentration was accomplished by reactive supttering at relatively high working pressure. In conventional reactive sputter-deposition of carbon nitride films, working pressure was 0.3-5Pa and the ratio of nitrogen to carbon(N/C ratio) in the films was less than 0.5. In this study, amorphous carbon nitride films with the N/C ratio $\tickapprox$ 1.0 were prepared on Si(100). substrates at higher pressure, 20-60 Pa. Structural analyses with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the films prepared consisted of triazine-like plain network.

• E2M - 전기 전자와 첨단 소재
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• 제8권1호
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• pp.13-20
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• 1995

To develope a high precision TiAIN thin film resistor, TiAIN films were deposited on A1$_{2}$03 substrates by reactive planar magnetron cosputtering from Ti and Al targets in an Ar-N$_{2}$ atmosphere. The characteristics of the TiAIN thin film were controlled by changing of the R.F. power on Ti and Al targets, and the N$_{2}$ partial pressure. The high precision TiAIN thin film resistor with TCR(Temperature Coefficient of Resistance) of less than 10ppm/.deg. C was obtained under the R.F. power condition of 160(w)/240(w) to Ti and Al targets at the N$_{2}$ partial pressure of 7*10$^{-5}$ Torr. The composition of these films were investigated by XRD, SEM and EDS.

• 약학회지
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• 제45권4호
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• pp.387-396
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• 2001

The effects of ascorbic acid, thiols such as cysteine, n-acetyl-ι-cyteine, glutathione, thiourea, 2-mercaptoethanol and dithiotreithol and organic acids such as magic acid, citric acid, glycolic acid, taurine and kojic acid on polyphenol oxidate (PPO) activity were studied in order to establish if it reacts with oxidized product and/or directly inhibits the enzyme. To investigate the mechanism, the quantification of t-butylcatechol and 4-methylcatechol (phenolic compounds) as substates, their oxidized product and sulphydryl colorless additional compounds were determined by high performance liquid chromatograph (HPLC) method. Chromatographic results indicate that ascorbic acid, organic acids and lower level of cysteine reduced oxidized product of substrates back to their respective positions uf ο-diphenols. On the other hand, other thiols and high level of cysteine reacted with oxidative product of ο-diphenols and then produced sulphydryl colorless compounds. Cysteine apperars to have two types of mechanism of actions in the formation of oxidative products of substrates depending on its concentration; ascorbic acid-type and other thiols-types. The effect of ascorbic acid with thiols on polyphenol oxidase was determined by same method. Chromatographic results indicate that ascorbic acid was more reactive with oxidized product of substrates than thiols.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.849-852
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• 2004

Indium tin oxide (ITO) thin films on polymeric substrates such as acryl (AC), Poly carbornate (PC), polypropylene (PP), and polyethlene terephthalate (PET) have been deposited by a do reactive magnetron sputtering without heat treatments. Sputtering parameters is an important factor for high Qualify of ITO thin films prepared on polymeric substrates. Furthermore, the material, electrical and optical properties of as-deposited ITO films are dominated by the ratio of oxygen partial pressure. As the experimental results the surface roughness of ITO films becomes rough as the oxygen partial pressure Increases. The electrical resistivity of as-deposited ITO films decreases initially, and then increases with the increase of oxygen partial pressure. The optical transmittance at visible wavelength for all polymeric substrates is above 80%.