• Title/Summary/Keyword: Scanning speed

Search Result 673, Processing Time 0.028 seconds

The Preferred Orientation of CdSe and CdS Thin Films on the AlOx and SiO2 Templates (AlOx와 SiO2 형판위 CdSe와 CdS 박막의 우선방위(Preferred Orientation) 특성)

  • Lee, Young-Gun;Chang, Ki-Seog
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.15 no.4
    • /
    • pp.502-506
    • /
    • 2012
  • In order to find the structural characteristics of the thin films of group II-VI semiconductor compounds compared with those of powder materials, films were made of 4 powders of ZnS, CdS, CdSe, and CdTe(Aldrich), each with 99.99 % purity. For the ZnS/CdS multi-layers, the ZnS layer was coated over the CdS layer on an $AlO_x$ membrane, which served as a protective layer within a vacuum at the average speed of 1 ${\AA}$/sec. After studying the structures of the group II-VI semiconductor thin films by using X-ray spectroscopy, we found that the ZnS, ZnS/CdS, CdS, and CdSe films were hexagonal and exhibited some degree of preferred orientation. Also, the particles of the thin films of II-VI semiconductor compounds proved to be more homogeneous in size compared to those of the powder materials. These results were further verified through scanning electron microscopy(SEM), EDX analysis, and powder and thin film X-ray diffraction.

Microprocess of silicon using focused Ar$^+$ llaser and estimates (집속된 아르곤 이온 레이저에 의한 실리콘의 미세가공 및 평가)

  • Cheong, Jae-Hoon;Lee, Cheon;Hwang, Kyoung-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1997.11a
    • /
    • pp.473-476
    • /
    • 1997
  • Focused Ar ion laser beam can be utilized to fabricate microstructures on silicon substrate as well as other materials(e.g. such as ceramic). The laser using in this study is an argon ion laser with maximum power of 6 W, wavelength of 514 nm. This laser beam is focused by objectives with a high numerical aperture, a long working distance. We have achieved line width about 1 ${\mu}{\textrm}{m}$ with high scan speed. The resolution for Si machining is determined by the selectivity of the chemical reaction rather than the laser spot size. In this study, we have obtained the maximum etch rate of 434.7 ${\mu}{\textrm}{m}$/sec with high aspect ratio. The characteristics of etched groove was investigated by scanning electron microscope(SEM) and auger electron spectroscopy(AES). It is assumed that the technique using arson ion laser is applicab1e to fabricate microstructures.

  • PDF

The Microstructures and Hot Extrudability of Semi-solid AM100A Magnesium Alloy Fabricated by Cooling Plate (냉각판으로 제조한 반응고 AM100A 마그네슘 합금의 미세조직 및 열간 압출성)

  • Kim, Dae-Hwan;Sung, Young-Rock;Shim, Sung-Yong;Lee, Sang-Yong;Kim, Kwang-Sam;Lim, Su-Gun
    • Journal of Korea Foundry Society
    • /
    • v.29 no.3
    • /
    • pp.144-149
    • /
    • 2009
  • In this study, we investigated optimum condition of cooling plate method to obtain semi-solid AM100A Mg alloy with fine and globular morphology. AM100A Mg alloy were hot extruded at $380^{\circ}C$ extrusion temperature under extrusion ratio of 25 : 1 and ram speed of 2.4 mm/sec. Vickers hardness test, optical microscopy, scanning electron microscopy, and image analyzer were performed to identify the optimum conditions of cooling plate method. Optimum conditions of cooling plate method to fabricate semi-solid AM100A Mg alloy with fine and globular microstructures were achieved at a pouring temperature of $602^{\circ}C$ and the angle of cooling plate of 60 degree.

Effects of Smooth and Textured Disks on Particle Generation in a Hard Disk Drive (하드 디스크 드라이브에서 Smooth 디스크와 LZT 디스크가 입자 발생에 미치는 영향)

  • Lee, Dae-Young;Huh, Sun-Young;Kang, Pil-Sun;Hwang, Jung-Ho;Cho, Keung-Youn;Kang, Tae-Sik
    • Transactions of the Society of Information Storage Systems
    • /
    • v.2 no.2
    • /
    • pp.123-129
    • /
    • 2006
  • The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated ill HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted particles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

  • PDF

Structural and Optical Characteristics of ZnS/CdS Powders and Thin Films (ZnS/CdS 분말과 박막의 구조 및 광학적 특성)

  • Chang, Ki-Seog
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.13 no.4
    • /
    • pp.659-664
    • /
    • 2010
  • The ZnS/CdS thin films were made using 99.99% ZnS and CdS(Aldrich) powders in $7{\times}10^{-6}torr$. The ZnS layer was coated over the CdS layer on an AlOx membrane within a vacuum, at the average speed of $1{\AA}/sec$. After studying the ZnS/CdS and CdS thin films(both with the dimensions of 2.52nm), using fluorescence spectroscopy and comparing the respective results together, we found that although both of the resulting spectra peaked at 390nm, the ZnS/CdS thin films showed a narrower peak, and a higher intensity of photoluminescence than the CdS thin films. The particles of ZnS/CdS thin films also proved to be more homogeneous in size. In addition, the ZnS layer acted as a protective layer. Also, after studying the spectra of ZnS/CdS thin films taken 30 days after their preparation, we found no signs of aging. These results were verified through the scanning electron microscopy(SEM), EDX analysis, thin film X-ray diffraction, and luminescence spectroscopy.

Laser Patterning of Indium Tin Oxide for Flat Panel Display (평판디스플레이를 위한 Indium Tin Oxide의 레이저 페터닝)

  • Ahn, Min-young;Lee, Kyoung-cheol;Lee, Cheon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2000.07a
    • /
    • pp.340-343
    • /
    • 2000
  • ITO(Indium Tin Oxide) films for transparent electrodes of FPD(Flat Panel Display) were patterned in atmosphere using laser. A pulse type(repetition rate of 10 Hz) Q-switched Nd:YAG laser which can generate the fundamental wavelength at 1064 nm or its harmonics(532, 266 nm) was used for Patterning of the ITO film. In case of using the second harmonic(532 nm) of Nd:YAG laser, the ITO film(thickness of 20 nm) was removed clearly with a laser fluence of 5.2 J/$\textrm{cm}^2$ and a beam scan speed of 200${\mu}{\textrm}{m}$/s. But the glass substrate was damaged when the laser fluence was over 5.2 J/$\textrm{cm}^2$. We discussed the etching mechanism of the ITO film using Nd:YAG laser with observation of the etching characteristics including a depths and widths of ITO films as a function of laser fluence using SEM(Scanning Electron Microscopy) and surface profiler($\alpha$-step 500).

  • PDF

Synthesis and Characteristics of Hyaluronic Acid Bead Crosslinked by 1,3-Butadiene diepoxide (1,3-Butadiene diepoxide에 의해 가교된 히아루론산 비드의 제조 및 특성)

  • Kwon, Ji-Young;Cheong, Seong-Ihl
    • Polymer(Korea)
    • /
    • v.29 no.5
    • /
    • pp.445-450
    • /
    • 2005
  • Hyaluronic acid-based beads were prepared in order to develop a biomedical material for augumentation. Hyaluronic acid was crosslinked by 1,3-butadiene diepoxide in a suspension state maintained by rapid mixing of soybeen oil and hyaluronic acid solution. The particle size, surface area and swelling ratio were measured to investigate the physical properties of the synthesized beads and the bead surface was examined by scanning electron microscopy. The beads were formed in the range of $5-12vol\%$ concentration of crosslinking agent, which showed monodisperse size distribution. Both BET surface area and swelling ratio decreased as the concentration of either hyaluronic acid or crosslinking agent increased, and crosslinking temperature decreased. Bead size could be effectively controlled by mixing speed without affecting other physical property.

Surface Texturing for Low Friction Mechanical Components

  • Iqbal, K. Y. Mohd;Segu, D. Z.;Pyung, H.;Kim, J. H.;Kim, S. S.
    • Tribology and Lubricants
    • /
    • v.31 no.6
    • /
    • pp.287-293
    • /
    • 2015
  • Laser surface texturing (LST), a surface engineering modification, has been considered as one of the new processes used to improve tribological characteristics of materials by creating artificially patterned microstructure on the contact surface of mechanical components. In LST technology, the laser is optimized to obtain or manufacture the dimples with maximum precision. The micro-dimples reduce the coefficients of friction and also improve the wear resistance of materials. This study investigates the effect of dimple density is investigated. For this purpose, a ball-on-disc type tester is used with AISI 52100 bearing steel as the test material. Discs are textured with a 5% and 10% dimple density. Experimental work is performed with normal loads of 5 N, 10 N, and 15 N under a fixed speed of 150 rpm at room temperature. The effect of the textured surface is compared to that of the untextured one. Experimental results show that the textured surface yields lower friction coefficients compared to those of untextured surfaces. Specifically, the 10% dimple density textured surface shows better friction reduction behavior than the 5% dimple density textured sample, and has an 18% improvement in friction reduction compared with the untextured samples. Microscopic observation using a scanning electron microscope (SEM) shows that the major friction mechanisms of the AISI 52100 bearing steel are adhesion, plastic deformation, and ploughing.

Effects of Sputter Parameters on Electrochromic Properties of Tungsten Oxide Thin Films Grown by RF Sputtering

  • Nah, Yoon-Chae
    • Korean Journal of Materials Research
    • /
    • v.21 no.12
    • /
    • pp.703-707
    • /
    • 2011
  • The electrochromic properties of tungsten oxide films grown by RF sputtering were investigated. Among the sputter parameters, first the $Ar:O_2$ ratios were controlled with division into only an $O_2$ environment, 1:1 and 4:1. The structure of each film prepared by these conditions was studied by X-ray diffraction, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. The sputter-deposited tungsten oxide films had an amorphous structure regardless of the $Ar:O_2$ ratios. The chemical compositions, however, were different from each other. The stoichiometric structure and low-density film was obtained at higher $O_2$ contents. Electrochemical tests were performed by cyclic voltammetry and chronoamperometry at 0.05 M $H_2SO_4$ solutions. The current density and charge ratio was estimated during the continuous potential and pulse potential cycling at -0.5 V and 1.8 V, respectively. The film grown in a higher oxygen environment had a higher current density and a reversible charge reaction during intercalation and deintercalation. The in-situ transmittance tests were performed by He-Ne laser (633 nm). At higher oxygen contents, a big transmittance difference was observed but the response speed was too slow. This was likely caused by higher film resistivity. Furthermore, the effect of sputtering pressure was also investigated. The structure and surface morphology of each film was observed by X-ray diffraction and scanning electron microscopy. A rough surface was observed at higher sputtering pressure, and this affected the higher transmittance difference and coloration efficiency.

Corrosion analysis of the duplex aluminum alloys (듀플렉스 알루미늄 합금의 내식성 분석)

  • Choi, In Kyu;Kim, Si Myeong;Kim, Sang Ho
    • Journal of the Korean institute of surface engineering
    • /
    • v.48 no.5
    • /
    • pp.227-232
    • /
    • 2015
  • Corrosion characteristic of the duplex Al-Mg-Si alloys with low, commercial and high solute contents were studied using an anodic polarization test in 1M NaCl solution at room temperature. Polarization range condition of the experiment were form .0.3V to .1.3V with a 0.2 mV scanning speed. The exchange current density means corrosion rate of the low solute alloy was low as about $16.29{\mu}A/cm^2$, and that of the high solute alloy was high as $84.92{\mu}A/cm^2$. The difference was mainly attributed to the inter-granular precipitates $Mg_2Si$ and Si which could make a galvanic corrosion on the aluminum base. The amount of precipitates was greater in high solute alloy at mainly in grain boundary. While, the extruded alloys had better corrosion resistance than the cast alloy because the silicon precipitates become coarse during the extrusion process.