• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2005.09a
• /
• pp.40-44
• /
• 2005

Catalytic performance of Co catalysts supported on MgO for the formation of multiwall carbon nanotubes (MWCNTs) Having 40-60 nm in diameter has been investigated through acetylene decomposition at $600^{\circ}C$. Scanning electron microscopy measurements show that the nanotubes are chain and coiled structures whereas x-ray diffraction patterns indicate the formation of MWCNTs with Co nanoparticles. In addition Raman spectra confirms the format ion of MWCNTs due to presence of characteristic radial breathing mode along with D and G bands.

• Current Optics and Photonics
• /
• v.3 no.4
• /
• pp.336-341
• /
• 2019

This paper proposes an optical system where the organic compound content in water is determined by using an ultraviolet (UV) LED (280 nm) and photodetector. The results obtained by the proposed prototype LED spectroscopy system, which includes a single photodetector and two parallel sample holders, are calculated by applying partial least square regression; the values are highly correlated with the actual concentrations of potassium hydrogen phthalate solutions, with an adjusted coefficient of determination about 0.996. Moreover, the total organic carbon values derived from the UV-Vis spectrometer of real samples (lake, river and sea water) differed little from those obtained by the LED spectroscopy. We confirm that the fast, sensitive, and compact LED sensor system can be readily configured for real-time monitoring of organic compounds in water.

• 한국전자현미경학회:학술대회논문집
• /
• 2000.05a
• /
• pp.65-67
• /
• 2000

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.75-75
• /
• 2003

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2006.10a
• /
• pp.31-34
• /
• 2006

(5n,5n) CNT 로 이루어져 있는 삼중벽 CNT(Carbon Nano Tube) 오실레이터의 진동을 분자동역학 시뮬레이션을 통해 연구하였다. 삼중벽 CNT 오실레이터의 진동수는 이중벽 CNT 오실레이터의 진동수보다 더 높은 것으로 관찰되었다.

• Journal of the Semiconductor & Display Technology
• /
• v.2 no.1
• /
• pp.21-24
• /
• 2003

Sludged silicon powders that are generated during silicon ingot slicing process have potential usage as silicon source in fabricating silicon carbide powders by adding carbon. A thermodynamic calculation is performed to consider a plausible formation condition for the silicon carbide powders. A thin silicon oxide layer around silicon powder is sufficient to supply equilibrium oxygen partial pressure at the formation temperature($1400^{\circ}C$) of the silicon carbide in the Si-C-O ternary system. Formation of silicon carbide by using the sludged silicon powders is more efficient than by using silicon oxide powders.

• Journal of the Semiconductor & Display Technology
• /
• v.6 no.1 s.18
• /
• pp.27-30
• /
• 2007

The gigahertz oscillator behavior of double-walled boron-nitride nanotube (BNNT) was investigated by using classical molecular dynamics simulations. The BNNT oscillator characteristics were compared to carbon-nanotube (CNT) and hybrid-C@BNNT oscillators. The results show that the BNNT oscillators are higher than the van der Waals force of the CNT oscillator. Since the frictional effects of BNNT oscillators are higher than that of a CNT oscillator, the damping factors of BNNT and hybrid oscillators are higher than that of a CNT oscillator.

• Journal of the Semiconductor & Display Technology
• /
• v.14 no.1
• /
• pp.55-59
• /
• 2015

This study demonstrates hybrid-type transparent electrodes for touch screen panels. The hybrid-type electrodes were fabricated by coating carbon nanotubes (CNTs) on metal meshes. To form the metal-meshes, thin films of silver (Ag) were deposited on glass substrates using the sputtering method and then patterned via photolithography to obtain mesh structures whose line width was $10{\mu}m$ and line-to-line spacing was $300{\mu}m$. CNTs were coated on Ag-meshes by using two different methods, such as spray coating and electrophoretic deposition (EPD). For the samples of a Ag-meshes and CNTs-coated Ag-meshes, their surface morphologies, electrical sheet resistances, and visible-range transmittances and reflectances were characterized and compared. The experimental results indicated that the reflectance of Ag-mesh electrodes was substantially reduced by coating of CNTs. Especially, the hybrid electrodes of Ag-meshes with EPD-coated CNTs showed excellent properties such as sheet resistance lower than $20{\Omega}/{\Box}$, transmittance higher than 90 %, and reflectance lower than 8%.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.2
• /
• pp.153-162
• /
• 2014

We show that carbon nanotube sensors with gold particles on the single-walled carbon nanotube (SWNT) network operate as Schottky barrier transistors, in which transistor action occurs primarily by varying the resistance of Au-SWNT junction rather than the channel conductance modulation. Transistor characteristics are calculated for the statistically simplified geometries, and the sensing mechanisms are analyzed by comparing the simulation results of the MOSFET model and Schottky junction model with the experimental data. We demonstrated that the semiconductor MOSFET effect cannot explain the experimental phenomena such as the very low limit of detection (LOD) and the logarithmic dependence of sensitivity to the DNA concentration. By building an asymmetric concentric-electrode model which consists of serially-connected segments of CNTFETs and Schottky diodes, we found that for a proper explanation of the experimental data, the work function shifts should be ~ 0.1 eV for 100 pM DNA concentration and ~ 0.4 eV for $100{\mu}M$.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.4
• /
• pp.119-124
• /
• 2011

Flow and temperature field in reactors are important factors for design of thermal chemical vapor deposition system to grow carbon nanotubes. In this study, effects of the variations of the inlet and outlet areas of the CVD reactor to the flow characteristics and temperature field are numerically analyzed. High temperature of the gas in the entrance region is obtained with slow gas speed resulted from the enlarged inlet area. Variation of the exit area has little effects on the flow field and temperature in the reactor. However the largest area among considered cases gives the highest gas temperature though the differences are small.