• 센서학회지
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• 제17권3호
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• pp.178-182
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• 2008

Planar type micro catalytic combustible gas sensor was developed by using nano crystalline $SnO_2$ Pt thin film as micro heater was deposited by thermal evaporation method on the alumina substrate. The thickness of the Pt heater was around 160 nm. The sensor showed high reliability with prominent selectivity against various gases(Co, $C_3H_8,\;CH_4$) at low operating temperature($156^{\circ}C$). The sensor with nano crystalline $SnO_2$ showed higher sensitivity than that without nano crystalline $SnO_2$. This can be explained by more active adsorption and oxidation of hydrogen by nano crystalline $SnO_2$ particles. The present planar-type catalytic combustible hydrogen sensor with nano crystalline $SnO_2$ is a good candidate for detection of hydrogen leaks.

• Journal of Korean Vacuum Science & Technology
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• 제2권2호
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• pp.97-100
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• 1998

We have investigated the effects of crystalline activation on solid phase crystallization (SPC) of amorphous silicon (a-Si) thin films. Wet blasting and self ion implantation were employed as the activation treatments to induce macro or micro crystalline damages on deposited a-Si films. Low temperature and larger grain crystallization were obtained by the applied two-step activation. High degree of crystallinity was also observed on both furnace and rapid SPC. crystalline activations showed the promotion of nucleation on the activated regions and the retardation of growth in an amorphous matrix in SPC. The observed behavior of two-step SPC was strongly dependent on the applied activation and annealing processes. It was also found that the diversified effects by macro and micro activations on the SPC were virtually diminished as the annealing temperature increased.

• 한국결정성장학회지
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• 제18권4호
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• pp.155-159
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• 2008

본 연구에서는 금속 Zn 팰렛을 원료 물질로 이용하여 열화학기상증착법으로 마이크로 크기의 프리스탠딩 ZnO/Zn 코어셀 다면체 구조물을 합성하였다. 마이크로 크기로 성장된 ZnO/Zn 코어셀 다면체의 형태와 구조적인 특성을 분석하기 위해서 주사전자현미경과 투과전자현미경을 이용하였다. 성장된 마이크로 크기의 다면체는 단결정 ZnO 나노막대 배열에 의해 둘러싸인 단결정 금속 Zn로 구성되어 있음을 확인할 수 있었다. 마이크로 크기의 단결정 Zn는 육방정 결정구조로 이루어져 있으며, 표면을 구성하고 있는 c-축 배향된 ZnO 나노막대가 10 nm와 100 nm 이하의 직경과 높이를 각각 가지며 육방정 결정구조의 단결정임을 확인하였다.

• 전기학회논문지
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• 제60권2호
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• pp.362-369
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• 2011

In this paper, optimal deep reactive ion etching (DRIE) process conditions for fused quartz were experimentally determined by Taguchi method, and fused quartz-based micro cantilevers were fabricated. In addition, comparative study on Q-factors of fused quartz and silicon micro cantilevers was performed. Using a silicon layer as an etch mask for fused quartz DRIE process, different 9 flow rate conditions of $C_4F_8$, $O_2$ and He gases were tested and the optimum combination of these factors was estimated. Micro cantilevers based on fused quartz were fabricated from this optimal DRIE condition. Through conventional silicon DRIE process, single-crystalline silicon micro cantilevers whose dimensions were similar to those of quartz cantilevers were also fabricated. Mechanical Q-factors were calculated to compare intrinsic damping properties of those two materials. Resonant frequencies and Q-factors were measured for the cantilevers having fixed widths and thicknesses and different lengths. The Q-factors were in a range of 64,000 - 108,000 for fused quartz cantilevers and 31,000 - 35,000 for silicon cantilevers. The experimental results supported that fused quartz had a good intrinsic damping property compared to that of single crystalline silicon.

• 한국광물학회지
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• 제17권4호
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• pp.339-355
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• 2004

국내산 고품위 석회석은 그 지질 배경과 광상 유형에 따라 (1) 제천-단양 지구, (2) 삼척-태백-정선 지구 및 (3) 울진-안동 지구의 유형들로 구분된다. 제천-단양 지구에서 산출되는 석회석을 제외한 대부분의 국내산 고품위 석회석들은 석회암이 열수변질작용과 열변성작용을 받아 재결정되고 Ca이 부화된 양상을 이룬다. 국내산 고품위 석회석은 광물조성, 화학조성, 결정도 및 광물상의 차이에 따라 결정질 석회암형, 대리암형, 미정질 및 거정질 방해석 유형으로 구분된다. 이들에 대해 응용광물학적 관점에서 그 조성과 특성을 밝히기 위한 체계적인 시험 및 분석이 이루어졌다. 제천-단양 지구의 고품위 석회석들은 외견상 원암에 가까운 결정질 석회암 유형으로서, 낮은 결정도와 세립질 조직, 비교적 높은 CaO 함량(51～54 wt.%) 및 낮은 백색도의 광석 특성을 갖는다. 삼척-태백-정선 지구에서 산출되는 미정질(대개 0.2～0.3 mm) 및 거정질(2～15 cm) 고품위 석회석은 전형적인 열수변질형 광석으로서, 결정도에서 유형별로 서로 현격한 차이를 보이고 다소 편차가 심한 CaO 함유도(50～55 wt.%) 및 높은 백색도를 보이는 것이 특징이다. 특히 이 지역의 주된 광체인 미정질 방해석형 광석은 미세하고 균일한 결정도와 보다 균질한 조성(대개 > 52 wt.%)을 이룬다. 울진-안동 지구의 변성퇴적암류에서 산출되는 석회석들은 그 광상 유형과 산출상태에 따라 품위와 품질면에서 현격한 차이를 보인다. 이 같은 국내산 고품위 석회석의 광물특성과 화학조성상의 특징에 의거하여 지역별로의 광석 유형에 따라 적절한_개발 용도를 제시하였다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.239-244
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• 2011

In this paper, we analyzed the electrical characteristics with crack pattern in crystalline solar cell. crystalline solar cells with a thin substrate, even small shocks can be easily damaged. Before the module goes through many processes, because the solar cells are at risk of a crack. That occurred early in the PV module micro-crack is not easily detection by eye test or output test. Because the EL (Electroluminescence) device has been detected using. PV module is made by laminated of a variety of materials. By different properties of each material will affect the crack. For this reason, the crack will grow and affect the output. And We analyzed the three crack patterns in crystalline solar cell. A growth of cracks on crystalline solar cell was interpreted by analysing generated cracks on the PV modules. Based on this interpretation, an electrical output value was calculated by mathematical modeling on electrical output characteristic with each crack patterns.

• 전기학회논문지
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• 제61권3호
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• pp.407-412
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• 2012

This study investigated the process of thermal-induced growth of micro-crack developed at the crystalline solar cell using EL image, determined the output characteristic according to the pattern of micro-crack, analyzed the I-V characteristic according to the pattern of crack growth, and predicted the output value using simulation. The purpose of this study was, therefore, to investigate the process of thermal-induced growth of micro-crack developed at the early stage of PV module completion using EL image, to analyze the resulting decrement of output and predict the output value using simulation. It was observed that the crack grew increasingly by the thermal condition, and accordingly the lowering of output was accelerated. The output values of crack patterns with various direction were predicted using simulation, resulting in close I-V curve with only around 4% of error rate. It is considered that it is possible to predict the electric characteristic of solar cell module using only pattern of micro-crack occurred at solar cell based on our results.

• Transactions on Electrical and Electronic Materials
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• 제4권3호
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• pp.29-33
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• 2003

Tri-crystalline silicon wafers have three different orientations and three-grain boundaries. In this paper, tri-crystalline silicon (tri-Si) wafers have been used for the fabrication of buried contact solar cells. The optical and micro-structural properties of these cells after texturing in KOH solution have been investigated and compared with those of cast mult- crystalline silicon (multi-Si) wafers. We employed a cost effective fabrication process and achieved buried contact solar cell (BCSC) energy conversion efficiencies up to $15\%$ whereas the cast multi-Si wafer has efficiency around $14\%$.

• 한국정밀공학회지
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• 제21권2호
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• pp.218-223
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• 2004

The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by Micro-lapping process. The sapphire crystalline wafers were characterized by double crystal X-ray diffraction. The sample quality of crystalline sapphire wafer at surface has a full width at half maximum of 250 arcsec. This value at the surface sapphire wafer surfaces indicated 0.12${mu}m$ sizes. Surfaces of sapphire wafers were mechanically affected by residual stress and surface default. As a result, the value of surface roughness of sapphire wafers measured by AFM(Atom Force Microscope) was 2.1nm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.82-85
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• 2003

The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by Micro-lapping process. The sapphire crystalline wafers were characterized by DCXD(Double Crystal X-ray Diffraction). The sample quality of crystalline sapphire wafer at surface has a FWHM(Full Width at Half Maximum) of 250 arcsec. This value at the sapphire wafer surfaces indicated 0.12${\mu}{\textrm}{m}$ sizes. Surfaces of sapphire wafers were mechanically affected by residual stress and surface default. Also Surfaces roughness of sapphire wafers were measured 2.1 by AFM(Atom Force Microscope).