• Applied Microscopy
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• 제33권3호
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• pp.179-185
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• 2003

일반적으로 전자현미경에 계기상 나타내는 가속전압에 의한 전자 빔의 파장은 실재로 시료 위에 입사되는 빔의 파장 값과는 다를 수 있다. 그러므로 적어도 한번은 계기상 나타난 전압에 대한 파장 값을 측정할 필요가 있다. 특히 QCBED 기법에서는 가능한 한 정확한 파장 값의 결정이 요구된다. 본 논문에서는 알려진 결정시료의 LACBED 패턴들로부터 정확하게 이 파장을 측정하는 간단한 방법을 제시한다. 이 방법은 이미 보고된 Kikuchi 패턴을 이용하는 기법과 유사하게 LACBED 패턴에서 같은 평면에 있지 않은 3개의 회절벡터에 의한 회절선이 거의 같은 점을 교차할 경우를 이용한다. 이 방법 적용 실험 예로써 알루미늄 결정시료를 사용하여 JEM2010전자현미경의 계기상 200 kv 가속전압에 대한 파장 값이 측정되었다. 측정된 파장과 대응되는 가속전압은 0.002496(3) nm과 $201.5{\pm}0.4$ kv이며 파장 값은 0.12%의 불확실성을 갖고 있다.

• 한국정밀공학회지
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• 제30권10호
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• pp.1009-1015
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• 2013

Ultra-short laser pulses are effective, when high requirements concerning accuracy, surface roughness and heat affected zone are demanded for surface structuring. In particular, picosecond laser systems that are suited to be operated in industrial environments are of great interest for many practical applications. This paper focused on inducing optimum process parameters for higher volume ablation rate by analyzing a relationship between crater diameter and optical spot size. In detail, the dependency of the volume ablation rate, penetration depth and threshold fluence on the pulse duration 8 ps and wavelength of 515 nm was discussed. The experimental results showed that wavelength of 515 nm resulted in less threshold fluence ($0.075J/cm^2$) on copper than IR wavelength ($0.3J/cm^2$). As a result, it was possible that optimum fluence for higher volume ablation rate was achieved with $0.28J/cm^2$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.525-525
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• 2013

Low temperature plasma diagnosis is one of the big issues in laboratory scale or processing industry. One of the most powerful techniques of plasma diagnostics is the use of the scattering of electromagnetic radiation from the plasma. Electron temperature and density are important parameters for understanding the information of plasmas in the plasma processing industry. Laser scattering experiments on plasma can provide a substantial amount of information about plasma parameters such as the electron density ne, the electron temperature Te, and the neutral density nn and temperature Tn. Thomson scattering spectroscopy is used several method, in accordance with detector type. Commonly, Thomson scattering is used several notch filter to separate expanded wavelength. Since using a spectrometer with surface relief grating or notch filter, the system of the measurement will be complicated and bigger. In this study, using VPHG (Volume Phase Holographic Grating) in order to install the simple and cheap system. VPHG has the advantage of the system installation, because it can be Transmission Type. The diffraction efficiency and dispersion angle of VPHG is higher than the surface relief grating relatively. For a wavelength and bandwidth selection, Using a slit or mask to select a rejection wavelength instead of notch filter.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.801-805
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• 2004

In this work, the fundamental study of on-line monitoring of $SiO_2$ particles in the size range of 40 nm to 725 nm was carried out using turbidimetry. The size of particle was measured using a field emission scanning electron microscope (FE-SEM). The factors affecting on the turbidity were discussed, for example, wavelength, size, and concentration. In order to observe the dependence of turbidity on the wavelength, a turbidimetric system equipped with charged coupled detector (CCD) was built. The shape of the transmitted peak was changed and the peak maximum was shifted to the red when the concentration of particle was increased. This result indicates that the turbidity is related to the wavelength, which corresponds to the characteristic of the Mie extinction coefficient, Q, that is a function of not only particle diameter and refractive index but also wavelength. It is clear that a linear calibration curve for each particle in different size can be obtained at an optimized wavelength.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.44-44
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• 2003

Free electron lasers (FEL) have, at least, the following advantages in comparison to conventional lasers： FEL can be designed for any arbitrary given emission wavelength. It is continuously tunable within wide band. Easy to get single-mode emission. Easily controlled emission structure (pulse duration, repetition rate, and pulse energy). (omitted)

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.29-37
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• 2021

A 7 nm technology node using extreme ultraviolet lithography with a wavelength of 13.5 nm has been recently developed and applied to the semiconductor manufacturing process. Furthermore, the development of sub-3 nm technology nodes continues to be required. In this study, design factors of an electrostatic deflector for an ultra-miniaturized microcolumn system that can realize an electron wavelength of below 1.23 nm with an acceleration voltage of above 1 eV were investigated using a three-dimensional simulator. Particularly, the optimal design of the electrostatic octupole floating deflector was derived by optimizing the design elements and improving the driving method of the 1 keV low energy ultra-miniaturized microcolumn deflector. As a result, the entire wide field of view greater than 330 ㎛ at a working distance of 4 mm was realized with an ultra-high-resolution electron beam spot smaller than 10 nm. The results of this study are expected to be a basis technology for realizing a wafer-scale multi-array microcolumn system, which is expected to innovatively improve the throughput per unit time, which is the biggest drawback of electron beam lithography.

• 한국정밀공학회지
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• 제33권5호
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• pp.363-369
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• 2016

We explored localized plasmonic field enhancements using nanowire patterns to improve the sensitivity of a surface plasmon resonance (SPR) sensor. Two different materials, gold and silver, were considered for sample materials. Gold and silver nanowire patterns were fabricated by electron beam lithography for experimental measurements. The wavelength SPR sensor was also designed for these experiments. The material-dependent field enhancements on nanowire patterns were first calculated based on Maxwell's equations. Resonance wavelength shifts were indicated as changes in the refractive index from 1.33 to 1.36. The SPR sensor with silver nanowire patterns showed a much larger resonance wavelength shift than the sensor with gold nanowire patterns, in good agreement with simulation results. These results suggest that silver nanowire patterns are more efficient than gold nanowire patterns, and could be used for sensitivity enhancements in situations where biocompatibility is not a consideration.

• 전자공학회논문지A
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• 제32A권1호
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• pp.200-205
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• 1995

The 1st and 2nd-order grating structure for long wavelength DFB(Distributed FeedBack) laser diodes are successfully fabricated on InP substrates by using electron beam lithography and reactive ion etch techniques, and also characterized non-destructively by diffraction analysis without removal of photo-resis layer. A new composite layer made by lifted-off Cr layer on thin SiO2 film is developed and used as an etch mask, because PMMA, the e-beamresist, is unsuitable for reactive ion etch of InP. In addition, it is experimentally confiremed that diffraction analysis makes it possible to predict the grating parameters, and the analysis can be used as a non-destructive on-line test to prevent incomplete gratings from being successively processed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.332-332
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• 2011

The extreme ultraviolet (EUV) radiation, whose wavelength is from 120 nm down to 10 nm, and the energy from 10 eV up to 124 eV, is widely utilized such as in photoelectron spectroscopy, solar imaging, especially in lithography and soft x-ray microscopy. In this study, we have investigated the plasma diagnostics as well as the debris characteristics between the two types of dense plasma focusing devices with coaxial electrodes of Mather and hypocycloidal pinch (HCP), respectively. The EUV emission intensity, electron temperature and plasma density have been investigated in these cylindrical focused plasma along with the debris characteristics. An input voltage of 5 kV has been applied to the capacitor bank of 1.53 uF and the diode chamber has been filled with Ar gas at pressure ranged from 1 mTorr and 180 mTorr. The inner surface of the cathode was covered by polyacetal insulator. The central anode electrode has been made of tin. The wavelength of the EUV emission has been measured to be in the range of 6~16 nm by a photo-detector (AXUV-100 Zr/C, IRD). The visible emission has also been measured by the spectrometer with the wavelength range of 200~1,100 nm. The electron temperature and plasma density have been measured by the Boltzmann plot and Stark broadening methods, respectively, under the assumption of local thermodynamic equilibrium (LTE).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.166.1-166.1
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• 2014

We have controlled the graphene surface in two ways to improve the device performance of optoelectronics based on graphene transparent conductive films. We controlled multilayer graphene (MLG) work function and localized surface plasmon resonance wavelength using a silver nanoparticles formed on graphene surface. Graphene substrates were prepared using a chemical vapor deposition and transfer process. Various size of silver nanoparticles were prepared using a thermal evaporator and post annealing process on graphene surface. Silver nanoparticles were confirmed by using scanning electron microscopy (SEM). Work functions of graphene surface with various sizes of Ag nanoparticles were measured using ultraviolet photoelectron spectroscopy (UPS). The result shows that the work functions of MLG could be controlled from 4.39 eV to 4.55 eV by coating different amounts of silver nanoparticles while minimal changes in the sheet resistance and transmittance. Also the Localized surface plasmon resonance (LSPR) wavelength was investigated according to various sizes of silver nanoparticles. LSPR wavelength was measured using the absorbance spectrum, and we confirmed that the resonance wavelength could be controlled from 396nm to 425nm according to the size of silver nanoparticles on graphene surface. To confirm improvement of the device performance, we fabricated the organic solar cell based on MLG electrode. The results show that the work function and plasmon resonance wavelength could be controlled to improve the performance of optoelectronics device.