• 센서학회지
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• 제19권2호
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• pp.87-91
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• 2010

Hydrogen gas sensors were fabricated using $PdO_x$ loaded with SWNTs. The nanoparticle powders of $SWNT_s-PdO_x$ composite were deposited on Si wafer substrates by a vacuum filtering deposition method. The fabricated sensors were tested against hydrogen gas. The composition ratio that exhibited the highest response to hydrogen gases was SWNTs : $PdO_x$ = 98 : 2 in wt% ratio at operating temperature of about $150^{\circ}C$. The response and recovery times were shorter than 1.0 min. in presence of 1000 ppm hydrogen.

• 센서학회지
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• 제18권2호
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• pp.179-183
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• 2009

Toluene($C_6H_5CH_3$) gas sensors were fabricated using $PtO_x$ loaded with SWNTs by a new deposition method. The nanoparticle powders of SWNTs-$PtO_x$ composite were deposited on Si wafer substrates by a vacuum filtering deposition method. The fabricated sensors were tested against toluene gas which is a kind of the Volatile Organic Compounds. The composition ratio that exhibited the highest response to toluene gases was SWNTs : $PtO_x\;=\;99:1$ in wt% ratio at operating temperature of about $150^{\circ}C$. The response and recovery times of the sensors were as short as less than 1 min., respectively.

• 한국진공학회지
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• 제6권S1호
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• pp.137-140
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• 1997

A cathodic arc with beam filter is employed for the deposition of metallic and hydrogen-free amorphous carbon films. A solenoid filter is used to prevent macropaticles and nonionized atoms from reaching the substrate. The detail transport characters of the filter are presented in the paper. With an optmum filter arrangement we are able to obtain a filter output of 18.4% of the total number of ions produced by the vacuum arc discharge. The deposited amorphous cabon thin film contains no hydrogen and a high fraction of $sp^3$ is determined by XPS. A dense Ti film deposited on H13 steel improves the corrosion resistance of the H13 steel and significant improvements of corrosion resistance were observed by implanting Ti, C in the film.

• 연구논문집
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• 통권30호
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• pp.147-157
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• 2000

The filtered vacuum arc source (FVAS), which is adopted by magnetic filtering methode to remove the macro-particle in vacuum arc plasma, was composed of a torus structure with bending angle of 60 degree. The radius of torus was 266 mm, the radius of plasma duct was 80 mm and the total length was 600 mm. The magnet parts were consisted of one permanent magnet, one magnetic yoke and five solenoid magnets. The plasma duct was electrically isolated from the ground so that a bias voltage could be applied. The baffles inside plasma duct were installed in order to prevent the recoil effect of macro-particles. Graphite was used as the cathode material to coat the amorphic diamond film and its diameter was 80 mm. The amorphic diamond film attracts much attention due to its excellent mechanical, optical and tribological properties suitable for wide range of applications. The effects of solenoid magnet in plasma extraction were studied by computer simulation and experiment using Taguchi's method. The source and extraction magnet affected the arc stabilization. The extraction beam current was maximized with low value of the source magnet current and high value of the filtering magnet current. Optimum deposition condition was obtained when the currents of arc discharge, source, extraction, bending, deflection and outlet magnet were 30 A, 1 A, 3 A, 5 A, and 5 A, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1379-1382
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• 1997

Diamond-like carbon(DLC) thin films are produced by using a filtered cathodic vacuum arc(FCVA) deposition system. Different magnetic components, namely steering, focusing, and filtering plasma-optic systems, are used to achieve a stable arc plasma and to prevent the macroparticles from incorporating into the deposited films. Effects of magnetic fields on plasma behavior and film deposition are examined. The carbon ion energy is found to be varied by applying a negative (accelerating) substrate bias voltage. The deposition rate of DLC films is dependent upon magnetic field as well as substrate bias voltage and at a nominal deposition condition is about $2{\AA}/s$. The structural properties of DLC films, such as internal stress, relative fraction of tetrahedral($sp^3$) bonds, and surface roughness have also been characterized as a function of substrate bias voltages and partial gas($N_2$) pressures.

• 한국진공학회지
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• 제10권4호
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• pp.431-439
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• 2001

비정질 다이아몬드 박막(amorphous-Diamond a-B)을 증착하기 위하여 제작된 Filtered Vacuum Arc Source (FVAS)는 60도의 굽힘 각도를 가지는 토러스형 구조로 토러스 반경 266 mm, 플라즈마 덕트 반경 80 % 전체 길이 600 mm이며, 1 개의 영구자석 및 5 개의 전자석으로 되어있다. 플라즈마 덕트는 임의의 전압을 인가할 수 있도록 전기적으로 절연 시켰으며, 덕트 내부는 배플을 설치하여 macro-particle의 되튐 현상을 방지하였다. 사용된 음극은 직경 80 mm의 graphite이다. 각 전자석이 플라즈마 인출에 미치는 영향은 taguchi 실험계획법을 이용, 수치 모사와 실험을 행하였다. 소스 전자석과 인출 전자석은 아크의 안정성에 영향을 주었고, 빔 인출 전류는 낮은 소스 전자석 전류와 특정한 필터 전자석 전류에서 최대값을 나타내었다. 이때 소스, 인출, 굽힘, 반사, 출구 전자석의 전류값은 1 A, 3 A, 5 A, 5 A, 5 A였으며, 아크 전류 30 A일 때, 빔 전류 밀도 3.2 mA/$\textrm{cm}^2$, 평균 증착률 5 $\AA$/sec를 얻었다. 또한 플라즈마 덕트의 바이어스 전압 증가에 따라, 빔 전류 밀도는 증가하였으며, 더 효율적인 빔을 인출할 수 있었다.

• E2M - 전기 전자와 첨단 소재
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• 제12권7호
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• pp.7-11
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• 1999

Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).