• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1315-1318
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• 2004

Nano-scale fabrication of silicon substrate in an aqueous solution based on the use of atomic force microscopy was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate easily by a simple scratching process (Tribo-Nanolithography, TNL), has been applied instead of conventional silicon cantilever for scanning. A slant nanostructure can be fabricated by a process in which a thin damaged layer rapidly forms in the substrate at the diamond tip-sample junction along scanning path of the tip and simultaneously the area uncovered with the damaged layer is being etched. This study demonstrates how the TNL parameters can affect the formation of damaged layer and the shape of 3-D structure, hence introducing a new process of proximal nanolithography in aqueous solution.

• 한국자기공명학회논문지
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• 제24권2호
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• pp.59-65
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• 2020

Nitrogen-Vacancy (NV) center in diamond has been an emerging versatile tool for quantum sensing applications. Amongst various applications, nano-scale nuclear magnetic resonance (NMR) using a single or ensemble NV centers has demonstrated promising results, opening possibility of a single molecule NMR for its chemical structural studies or multi-nuclear spin spectroscopy for quantum information science. However, there is a key challenge, which limited the spectral resolution of NMR detection using NV centers; the interrogation duration for NV-NMR detection technique has been limited by the NV sensor spin lifetime (T₁ ~ 3ms), which is orders of magnitude shorter than the coherence times of nuclear spins in bulk liquid samples (T₂ ~ 1s) or intrinsic ¹³C nuclear spins in diamond. Recent studies have shown that quantum memory technique or synchronized readout detection technique can further narrow down the spectral linewidth of NMR signal. In this short review paper, we overview basic concepts of nanoscale NMR using NV centers, and introduce further developments in high spectral resolution NV NMR studies.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.538-541
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• 2003

Ultra-precision machining was carried out on a electroless nickel materials using single crystal diamond tools. The effects of the cutting velocity, the tool length, the tool nose radius, the feed rate and depth of cut on the surface roughness were studied. In this paper, the cutting condition for getting nano order smooth surface of electroless nickel have been examined experimentally by the ultra-precision machine and single crystal diamond tools. And also. the surface roughness was measured by the three dimension

• Transactions on Electrical and Electronic Materials
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• 제7권3호
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• pp.118-122
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• 2006

Diamond-like carbon (DLC) films were prepared on silicon substrates by the RF PECVD (Plasma Enhanced Chemical Vapor Deposition) method using methane $(CH_4)$ and hydrogen $(H_2)$ gas. We examined the effects of the post annealing temperature on the tribological properties of the DLC films using friction force microscopy (FFM). The films were annealed at various temperatures ranging from 300 to $900^{\circ}C$ in steps of $200^{\circ}C$ using RTA equipment in nitrogen ambient. The thickness of the film was observed by scanning electron microscopy (SEM) and surface profile analysis. The surface morphology and surface energy of the films were examined using atomic force microscopy and contact angle measurement, respectively. The hardness of the DLC film was measured as a function of the post annealing temperature using a nano-indenter. The tribological characteristics were investigated by atomic force microscopy in FFM mode.

• 한국재료학회지
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• 제10권9호
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• pp.648-655
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• 2000

다이아몬드 합성 조건에서 질소 첨가량은 0%에서 95%까지 변화하였을 때의 합성 거동을 조사하였다. 질소 첨가량이 증가함에 따라 합성된 상은 {100} 성장면으로 이루어진 다이아몬드 막에서 고유의 결정면이 사라지고 나조 크기의 결정들로 이루어진 다이아몬 막으로 변화하였다. 심지어 수소가 없어 메탄과 질소만의 경우에서도 다이아몬드 막 합성이 가능함을 보여주었다. 또한 다이아몬드 구조를 갖는 개별적 입자의 형태는 30%∼80% 질소 첨가범위에서 정팔면체의 결정모양을 가졌고, 이 범위에서 기판온도가 증가함에 따라 육방정 모양의 새로운 결정상을 관찰하였다. 다이아몬드 막의 경우 질소, 첨가량에 무관하게 질소 혼입향은 측정되지 않을 만큼 적었지만, 육방정 결정상은 Si, C 그리고 N으로 이루어진 SiCN화합물임을 확인하였다.

• 한국재료학회지
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• 제21권3호
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• pp.149-155
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• 2011

We investigated tribological characteristics of diamond-like carbon (DLC) in a condition with carbon nanotube (CNT) content of 1wt% in aqueous solution. Si-DLC films were deposited by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) process on Al6061 aluminum alloy. In this study, the deposition of DLC films was carried out in vacuum with a chamber pressure of 10-5 to 10-3 Torr achieved by mechanical pump followed by turbo molecular pump. The surface adsorbed oxygen on the Aluminum substrates was removed by passing Ar gas for 10 minutes. The RF power was maintained at 500W throughout the experiment. A buffer layer of HMDSO was deposited on the substrate to improve the adhesion of DLC coating. At this point CH4 gas was introduced in the chamber using gas flow controller and DLC coating was deposited on the buffer layer along with HMDSO for 50 min. The thickness of 1 ${\mu}m$ was obtained for DLC films on aluminum substrates The tribological properties of as synthesized DLC films were analyzed by wear test in the presence of dry air, water and lubricant such as CNT ink.

• Current Photovoltaic Research
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• 제6권1호
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• pp.1-11
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• 2018

Current major photovoltaic (PV) market share (> 60%) is being occupied by the multicrystalline (mc)-silicon solar cells despite of low efficiency compared to single crystalline silicon solar cells. The diamond wire sawing technology reduces the production cost of crystalline silicon solar cells, it increases the optical loss for the existing mc-silicon solar cells and hence its efficiency is low in the current mass production line. To overcome the optical loss in the mc-crystalline silicon, caused by the diamond wire sawing, next generation texturing process is being investigated by various research groups for the PV industry. In this review, the limitation of surface structure and optical loss due to the reflectivity of conventional mc-silicon solar cells are explained by the typical texturing mechanism. Various texturing technologies that could minimize the optical loss of mc-silicon solar cells are explained. Finally, next generation texturing technology to survive in the fierce cost competition of photovoltaic market is discussed.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.808-811
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• 2008

Optical and mechanical properties of diamond-like carbon (DLC) films synthesized by RF plasma enhanced chemical vapor deposition were investigated as a function the C/H ratio in gas mixture. The C/H ratio was varied from 6 to 10 %, adjusting the amount of $CH_4$ and $H_2$ as the source gas. The optical and mechanical properties of DLC films were characterized by UV spectrometer, Ellipsometer and Nano-indenter. The change of the C/H ratio during synthesis of DLC films had many effects on the growth rate, transmittance, refractive index and hardness. The growth rate of the films increased exponentially with the increase in C/H ratio. The hardness of the films showed the tendency to improve with increasing C/H ratio, whereas the transmittance decreased. The refractive index was varied from 2.03 to 2.17, and these refractive indexes close to 2.0 indicates that it can be applied to Si-based solar cell.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.32-38
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• 2008

This paper describes a fast tool control (FTC)-based diamond turning process for fabricating large-area high-quality micro-lens arrays. The developed FTC unit has a stroke of $48{\mu}m$ and a resonance frequency of 4.9 kHz. Micro-lens arrays were fabricated using a micro-cutting tool with a nose radius of $50{\mu}m$. The FTC unit was integrated with a force sensor so that the initial position of the micro-cutting tool with respect to the workpiece surface could be detected through monitoring the contacting force. The length and depth of the designed parabolic micro-lens profile were $190{\mu}m$ and $20{\mu}m$, respectively. A micro-lens array was fabricated on a cylinder surface over an area of ${\phi}55 mm{\times}40 mm$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.947-949
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• 2012