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금 박막의 마이크로 인장 특성 측정 : 시험편 크기 영향
허용학(Yong-Hak Huh),김동일(Dong-Iel Kim),기창두(Chang-Doo Kee),연순창(Soon-Chang Yeon),김용협(Yong-Hyup Kim) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.8
Tensile properties of gold thin film were evaluated using micro-tensile testing system. Gold thin films 0.5㎛ and 1.0㎛ thick were produced by sputtering and three kinds of the specimen 50㎛, 100㎛ and 200㎛ wide were prepared by micro-machining. From the tensile tests of the various specimens, dependency of thickness and width on the 0.2% yielding strength, tensile strength and elastic modulus was examined. It was shown that 0.2% yielding strength and tensile strength increased with increase of the width, while those decreased with the increase of the thickness. Elastic modulus was measured in the range of 51~59㎬. Furthermore, dependency of the test speed on the tensile properties was investigated. It was said that those obtained in the range of 25㎛/min and 75㎛/min were nearly identical.
복합도금법으로 형성된 탄소나노튜브-구리 복합구조물의 전계방출특성
성우용(Woo-Yong Sung),김왈준(Wal-Jun Kim),이승민(Seung-Min Lee),유형석(Hyeong-Suk Yoo),이호영(Ho-Young Lee),주승기(Seung-Ki Joo),김용협(Yong-Hyup Kim) 한국표면공학회 2005 한국표면공학회지 Vol.38 No.4
Carbon nanotube-copper composite structures were fabricated using composite plating method and their field emission characteristics were investigated. Multi-walled carbon nanotubes (MWNTs) synthesized by chemical vapor deposition were used in the present study. It was revealed that turn-on field was about 3.0 V/㎛ with the current density of 0.1 ㎂/㎠ We observed relatively uniform emission characteristics as well as stable emission current. Carbon nanotube-copper composite plating method is efficient and it has no intrinsic limit on the deposition area. Moreover, it gives strong adhesion between emitters and an electrode. Therefore, we recommend that carbon nanotube-copper composite plating method can be applied to fabricate electron field emitters for large area FEDs and large area vacuum lighting sources.
습식공정으로 형성된 구리산화물 나노와이어의 전계방출특성 향상
섬우용(Woo-Yong Sung),김왈준(Wal-Jun Kim),이승민(Seung-Min Lee),이호영(Ho-Young Lee),박경호(Kyung-Ho Park),이순일(Soonil Lee),김용협(Yong-Hyup Kim) 한국표면공학회 2004 한국표면공학회지 Vol.37 No.6
Vertically-aligned and uniformly-distributed CuO nanowires were formed on copper-coated Si substrates by wet chemical process, immersing them in a hot alkaline solution. The effects of hydrogen plasma treatment on the field emission characteristics of CuO nanowires were investigated. It was found that hydrogen plasma treatment enhanced the field emission properties of CuO nanowires by showing a decrease in turn-on voltage, and an increase in emission current density, and stability of current-voltage curves. However, the excessive hydrogen plasma treatment made the I-V curves unstable. It was confirmed by XPS (X-ray Photoelectron Spectroscopy) analysis that hydrogen plasma treatment deoxidized CuO nanowires, thereby the work function of the nanowires decreased from 4.35 eV (CuO) to 4.1 eV (Cu). It is thought that the decrease in the work function enhanced the field emission characteristics. It is well-known that the lower the work function, the better the field emission characteristics. The results suggest that the hydrogen plasma treatment is very effective in achieving enhanced field emission properties of the CuO nanowires, and there may exist an optimal hydrogen plasma treatment condition.
금 박막에서 마이크로 인장 특성에 대한 입자 크기 영향
김동일(Dong-Iel Kim),허용학(Yong-Hak Huh),기창두(Chang-Doo Kee),연순창(Soon-Chang Yeon),김용협(Yong-Hyup Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
Micro-tensile tests for Au thin films with three different thicknesses were carried out to investigate the effect of the grain size on tensile properties. Au thin films with the respective thickness of 0.18, 0.5 and 1.0 ㎛ were produced by sputtering and micro-tensile specimens 2 ㎜ long and 200 μ wide were fabricated using micro-machining process. Tensile stress-strain curves, showing elasitc-plastic behavior, were obtained using the strain measurement system, i.e. micro-ESPI system, developed in this study. From these curves, 0.2% yielding strength, tensile strength and elastic modulus, were determined. It was found that these values were dependent on the grain size of the films. Furthermore, in this study, the effect of the width of the specimens was also investigated.