• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.1
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• pp.47-52
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• 2008

We present a 3-D profiler specially devised for the profile measurement of rough surfaces that are difficult to be measured with conventional non-contact interferometer. The profiler comprises multiple two-point-diffraction sources made of single-mode optical fibers. Test measurement proves that the proposed profiler is well suited for the warpage inspection of microelectronics components with rough surface, such as unpolished backsides of silicon wafers and plastic molds of integrated-circuit chip package.

• Journal of the Korean Ceramic Society
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• v.44 no.2 s.297
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• pp.84-88
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• 2007

CdSe hollow spheres with the diameter of about 30-50 nm were synthesized after ultrasonic irradiation in the presence of $Cd(NO_3)_2,\;Na_2SeSO_3$, and polyvinylalcohol(PVA). The characteristics of CdSe hollow spheres were analyzed using X-ray diffraction(XRD), transmission electron microscopy(TEM), UV-vis measurement and PL spectrometer. The characteristics of solvent as water and water-1-propanol mixture in the system played important roles on the controlled synthesis of hollow sphere. Based on the observation of morphological difference of CdSe, the possible mechanism of CdSe hollow sphere formation will be discussed.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.68-71
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• 2003

In this paper, We have investigated the luminous flux, luminous efficacy, spectral energy distribution, colour rendering index, correlated colour temperature of electrodeless QL lamp system as a center method of measurement and side method of measurement. A result of measurement is that center method of measurement and side method of measurement is almost similar. Therefore, Sample that didn't measured because of big size and heavy weight can be measured by center method of measurement.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.12
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• pp.585-587
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• 2005

In this paper, We studied two methods to measure optical characteristics of an electrodeless light source using the integrating sphere(diameter 1.5m). One is to use a center measurement method and the other is to use a side measurement method. As a result of analysis, a side measurement methode without auxiliary lamp is almost similar against a center measurement with auxiliary lamp to reduce a measurement of an error for luminous flux, luminous efficacy and spectral distribution etc. Therefore, Sample which cannot measured by reason of big size and heavy weight can be measured by a side measurement method.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.294-303
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• 2021

Various types of sensors are used at industrial sites to measure vibration. With the increase in the diversity of vibration measurement methods, vibration monitoring methods using camera equipment have recently been introduced. However, owing to the physical limitations of the hardware, the measurement resolution is lower than that of conventional sensors, and real-time processing is difficult because of extensive image processing. As a result, most such methods in practice only monitor status trends. To address these disadvantages, a high-resolution vibration measurement method using image analysis of the edge region of the structure has been reported. While this method exhibits higher resolution than the existing vibration measurement technique using a camera, it requires significant amount of computation. In this study, a method is proposed for rapidly processing considerable amount of image data acquired from vision equipment, and measuring the vibration of structures with high resolution. The method is then verified through experiments. It was shown that the proposed method can fast measure vibrations of structures remotely.

• Journal of Sensor Science and Technology
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• v.8 no.6
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• pp.476-480
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• 1999

PbSe thin films were grown using PLD method on the p-Si(100) substrate. To determine what crystalline structure of PbSe thin films have according to the growth temperature, the films were prepared under a substrate temperature changing between a room temperature and $400^{\circ}C$. As a result of analyzing XRD patterns of PbSe thin films prepared at various substrate temperatures and FWHM of PbSe(200) rocking curve, it was found that PbSe thin film obtained at the growth temperature of $200^{\circ}C$ was best crystallized. In addition, the surface morphology of PbSe thin film observed using AFM found itself having the most regularly arranged particles in case of growing the film at $200^{\circ}C$. The measurement of Hall effect indicated that PbSe thin films were n-type semiconductors and that current-voltage characteristic curve exhibit the typical p-n junction phenomenon. In addition, electric conductivity of PbSe thin films was found somewhat higher than that of general semiconductors.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.105-110
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• 1997

1μm-CdS films for a window layer of CdS/CuInSe2 solar cell have been prepared by vacuum of 1x10-3 mTorr. Source and substrate temperature ranges were used 800-1100'C and 50-200℃ respectively. Structural, electircal and optical properties of CdS films have been investigated by X-ray diffractometer (XRD), scanning electron microscopy (SSEM), electrical resistivity, the Hall measurement and optical transmission spectra. Electrical resistivity and optical transmission of the CdS films decreased with the increase in CdS source temperature without substrate heating. All the films had hexagonal structure and strong texture with (002) orientation of grain normal to the substrate glass. CdS films evaporated at 1000℃ were the highest electrical conductivity of 0.9(S/cm). Electrical resistivity and optical transmission at the substrate temperature of 100℃ were 40(Ω,cm) and 80% respectively.

• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.250-254
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• 2007

Applying the moving photo-carrier grating(MPG) technique and time-of-flight(TOF) measurements, we studied the transport properties of stabilized amorphous selenium typical of the material used in direct conversion X-ray imaging devices. For MPG measurement, we obtained electron and hole mobility and the recombination lifetime of $\alpha-Se$ films with arsenic(As) additions. We found an apparent increase in hole drift mobility and recombination lifetime, especially when 0.3 % As was added into $\alpha-Se$ film, whereas electron mobility decreased with the addition of As due to the defect density. For TOF measurement, a laser beam with pulse duration of 5 ns and wavelength of 350 nm was illuminated on the surface of $\alpha-Se$ with a thickness of 400 ${\mu}m$. The measured hole and electron transit times were about 8.73 ${\mu}s$ and 229.17 ${\mu}s$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.146-147
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• 2009

$CuGaSe_2$ (CGS) layers were grown by the hot wall epitaxy method. The optimum temperatures of the substrate and source for growth turned out to be 450 and $610^{\circ}C$, respectively. Based on the absorption measurement, the band-gap variation of CGS was well interpreted by the Varshni's equation. By analyzing these emissions, a band diagram of the observed optical transitions was obtained. From the solar cell measurement, an 11.17 % efficiency on the n-CdS/p-CGS junction was achieved.

• Journal of the Korean Electrochemical Society
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• v.14 no.3
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• pp.145-151
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• 2011

ZnSe, as a II-VI compound semiconductor which has a wide band gap in the visible region is applicable to the various fields such as laser diode, display and solar cell. By using the electrochemical deposition method, ZnSe thin film was synthesized on the ITO glass substrate. The synthesis of ZnSe grains and their structure having zinc blende shape were verified through the analysis of XRD and SEM. UV spectrophotometric method determined the band gap as the value of 2.76 eV. Applying the DFT (Density Functional Theory) in the molecular dynamics, the band structure of ZnSe grains was analyzed. For ZnSe grains with zinc blende structure, the band structure and its density of state were simulated using LDA (Local Density Approximation), PBE (Perdew Burke Ernzerhof), and B3LYP (Becke, 3-parameter, Lee-Yang-Parr) functionals. Among the calculations of energy band gap upon each functional, the simulated one of 2.65 eV based on the B3LYP functional was mostly near by the experimental measurement.