• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.182-183
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• 2003

자체집광(Self-focusing)현상은 매우 높은 집적도를 가지는 광기록매체의 제작에 응용 가능하기 때문에 많은 연구자들에 의해 광범위하게 연구되어왔다. 그동안의 연구에서는 자체집광에 대한 분석방법으로서 빛살의 벡터특성을 무시한 비선형 슈뢰딩거 방정식(nonlinear Schr dinger equation)을 이용하였는데, 이 경우 축상으로 대칭적인 빛살이 입사될 때 발생되는 다중 필라멘테이션(Multiple Filamentation)현상은 입사빛살에 첨가되는 random noise에 기인한다는 것이 유일한 해석방법이었다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.260-261
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• 2002

For Near-field Scanning Optical Microscopy measurements, the fiber tip is glued on the side of one of the tuning fork prongs vertically to its extended direction. Higher Q-factor is attainable in this geometry than in the arrangement with the fiber tip parallel to the prong. A simple mechanical design is applied to hold the fiber tip above the gluing point. The overall tuning fork-fiber tip assembly gives another advantage of the flexible Q-factor enhancement. With this treatment, Q-factor higher than 3000 is easily achievable. As an operating instance, a grating is scanned for its one dimensional topographical image.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.190-191
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• 2003

물질에 큰 전기장을 가하였을 때 그 물질의 전기 감수율이 선형이 아닌 비선형관계를 갖게 되는데, 이로 인하여 선형계에서는 볼 수 없는 여러 가지 특이한 현상들이 관측된다. 이러한 비선형적인 현상 중에서 자체집광현상은 Guassian세기 분포를 가지는 빛을 매질에 통과시켰을 때 시료가 얇은 렌즈처럼 작용하는 것으로 설명할 수 있다. 비선형 효과에 의하여 레이저빔이 본래의 특성과 달라질 수 있고 빔의 심각한 변형을 일어난다. (중략)

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.859-862
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• 2003

Well-aligned multiwall carbon nanotubes (MWCNTs) were prepared at low temperature of 400 $^{\circ}C$ by utilizing a radio frequency plasma-enhanced chemical vapor deposition (rf-PECVD) system. The MWCNTs were treated by an external rf plasma source and an ultra-violet laser in order to modify structural defect of carbon nanotube and to ablate possible contamination on carbon nanotube surface. Structural properties of carbon nanotubes were investigated by using a scanning electron microscopy (SEM), Raman spectroscopy, Fourier transformer Infrared spectroscopy (FTIR) and transmission electron microscope (TEM). In addition, the emission properties of the MWNTs were measured for the application of field emission display (FED) in near future. Various post treatments were found to improve the field emission property of carbon nanotubes.

• Journal of the Optical Society of Korea
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• v.9 no.1
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• pp.16-21
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• 2005

Using a cantilever type nanoprobe having a 100㎚m aperture at the apex of the pyramidal tip of a near-field scanning optical microscope (NSOM), nanopatterning of polymer films are conducted. Two different types of polymer, namely a positive photoresist (DPR-i5500) and an azopolymer (Poly disperse orange-3), spincoated on a silicon wafer are used as the substrate. A He-Cd laser with a wavelength of 442㎚ is employed as the illumination source. The optical near-field produced at the tip of the nanoprobe induces a photochemical reaction on the irradiated region, leading to the fabrication of nanostructures below the diffraction limit of the laser light. By controlling the process parameters properly, nanopatterns as small as 100㎚ are produced on both the photoresist and azopolymer samples. The shape and size variations of the nanopatterns are examined with respect to the key process parameters such as laser beam power, irradiation time or scanning speed of the probe, operation modes of the NSOM (DC and AC modes), etc. The characteristic features during the fabrication of ordered structures such as dot or line arrays using NSOM lithography are investigated. Not only the direct writing of nano array structures on the polymer films but also the fabrication of NSOM-written patterns on the silicon substrate were investigated by introducing a passivation layer over the silicon surface. Possible application of thereby developed NSOM lithography technology to the fabrication of data storage is discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.50-50
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• 2011

The aluminum nitride films were prepared by RF magnetron sputtering using an AlN ceramic target. The crystallinity, grain size, Al-N bonding and thermal conductivity were investigated in dependence on the plasma power densities (4.93, 7.40, 9.87 W/$cm^2$) during sputtering. High thermal conductivity is important properties of A1N passivation layer for functioning properly in thermal inkjet printhead. The crytallinity, grain size, Al-N bonding formation and chemical composition were observed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. The AlN thin film was changed from amorphous to crystalline as the power density was increased, and the largest grain size appeared at medium power density. The near stoichiometry Al-N bonding ratio was acquired at medium power density. So, we know that the AlN thin film had better thermal conductivity with crystalline phase and near stoichometry Al-N bonding ratio at 7.40 W/$cm^2$ power density.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.108-111
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• 2000

We will illustrate the topographical structure and optical structure of the merocyanine dye LB films obtained by the scanning near-field optical/atomic force microscopy (SNOAM). SNOAM was recognized as a powerful tool to modify the surface as well as to characterize the topography of the surface at atomic resolution, especially for optical reaction materials. SNOAM images showed that the topographical and optical structures of these films were not only depended on the chemical property but also physical property. In the continuous measurement on these dyes, the appearance of near-field optical transmission images showed a certain dependence on the kinds of dyes and the mutual mixing ratios of dyes. These experimental results suggest that there is a certain kind of interaction between these two dyes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.526-530
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• 2004

We report the space charge and the surface potential of the interface between metal and CuPc according to isotropic property and different metal by measuring the microwave reflection coefficients $S_{11}$ of copper(II)-phthalocyanine(CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand. CuPc thin films were prepared on gold and aluminium substrates using a thermal evaporation method. Two kinds of CuPc thin films were prepared. One was deposited on preheated substrate at $150^{\circ}C$ and the other was annealed after deposition by using thermal evaporation methods. The microwave reflection coefficients $S_{11}$ of CuPc thin films were changed by the dependence on the heat treatment conditions. By comparing reflection coefficient $S_{11}$ we measured electrical conductivity of CuPc thin films and studied this results with respect to the surface potential and space charge of the interface between metal and CuPc thin films.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.341-349
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• 2021

We studies to verify results similar to those of previous experiments, and their potential as a lighting device through optical characteristics experiments and resonance and optical characteristics simulations of array devices. The photonic quantum ring (PQR) device having a mesa diameter of 40 ㎛ and an internal hole diameter of 3 ㎛ was fabricated. Through the near-field observation of the fabricated device, it was found that the PQR device operates even at ㎂, and also that the mesa and hole devices are driven independently of each other. As a result of measuring the wavelength spectrum of the device according to the location, the coupling phenomenon due to mesa and holes was confirmed.

• Vacuum Magazine
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• v.3 no.4
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• pp.14-18
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• 2016

In this article, we will summarize recent advances in ultrahigh vacuum (UHV) low-temperature scanning tunneling microscopy (STM) during the last decade. Leading STM groups have finished or are constructing UHV milli-Kelvin high magnetic field STM capable of a few tens of milli-Kelvin and ~ 10 tesla. Applications with UHV sub-Kelvin high magnetic STM have been increased since mid-2000's. Active research using UHV low temperature tuning fork atomic force microscopes and UHV photon low-temperature scanning tunneling microscopes will be introduced. Considering these advances of UHV low-temperature STM we will discuss next trend in STM in the near future.