• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
• /
• pp.36-41
• /
• 2011

BIPV system that can alternate building envelope by making materials of PV module should be considered in initial design step for applying PV system efficiently in office building. Mean while, area of the building skin also increases as the number of floors increases, but the valid area that can apply BIPV system in effect decreases relatively. Despite of this weak point, installing BIPV system is still being evaluated as the only measure left that can reduce electronic energy consumption in the building. Therefore, the impact on building energy consumption according to the increase of the number of floors when BIPV system is applied in the building was analyzed. And it will be used as basic information for application of BIPV in office building. Conomic about application of BIPV is interpreted to be secured within the 10 story high. Forover the 11 floors, the methods of increasing the contribution ratio produced by BIPV system through the optimization of install angle and increase in install area of south, high efficiency should be considered. The ways to reduce basic load by integrated design with another renewable energy besides BIPV should be found. Later, the study on the total building energy comsumption with PV generation according to the various type of the basic load and ratio of the width and depth will be performed based on this study.

• 대한전자공학회논문지SD
• /
• 제37권4호
• /
• pp.31-37
• /
• 2000

금속 유도 측면 결정화 (Metal-Induced Lateral Crystallization; MILC)에 의해 저온다결정 실리콘 박막트랜지스터를 형성할 때 Ni박막을 게이트와 소오스/드레인간 경계로부터 거리를 달리하여 형성한 뒤 결정화시킴으로써 소오스와 드레인으로부터 결정화가 진행되어 서로 만나는 경계 면을 채널 내부 외부에 인위적으로 위치시킬 수 있었고 이들의 전기적 특성비교를 통하여 MILC경계가 트랜지스터 특성에 미치는 영향을 고찰할 수 있었다. MILC 경계를 채널 내부로부터 제거시킴으로써 On Current, Subthreshold slope 특성을 향상시킬 수 있었고 누설전류 특성도 크게 향상시킬 수 있었다. 채널 내부에 MILC 경계가 존재할 경우 전기적 스트레스를 인가함에 따라 누설전류의 양이 감소하였고, 전체 감소량은 채널 폭이 넓을수록 증가하였고 채널길이에는 무관하였다.

• 한국전기전자재료학회논문지
• /
• 제25권8호
• /
• pp.646-650
• /
• 2012

Multifunctional structures with two kinds of materials have been intensively investigated in order to improve their electrical characteristic with two functions simultaneously. However, the research regarding of multifunctional ceramic sensor is still in a preliminary stage and how to integrate them with low-cost and high-yield mass production process remains a challenge issue. In this study, we fabricated the multifunctional ceramic sensor composed of temperature and gas sensors. Moreover, we investigated the CO sensing properties of three dimensional nanostuctured $Nb_2O_5$ thin film gas sensors fabricated with silica ($SiO_2$ nanosphere (${\O}$= 750 nm). Compared to plain films, the nanostructured films show enhanced gas sensing of greater sensitivity and a faster response. This result reveals that significantly increased sensitivity is an increase in the effective surface area for the adsorption of gas molecules.

• 한국전기전자재료학회논문지
• /
• 제26권1호
• /
• pp.44-48
• /
• 2013

Niobium oxide($Nb_2O_5$) films were deposited on p-type Si wafers at room temperature using in-line pulsed-DC magnetron sputtering system with various frequencies. The different duty ratios were obtained by varying the frequency of pulsed DC power from 100 to 300 kHz at the fixed reverse time of $1.5{\mu}s$. From the thickness of the sputtered $NbO_x$ films, it was possible to obtain much higher deposition rate in case of pulsed-DC sputtering than RF sputtering. However, the similar leakage currents and structural characteristics were obtained from the metal-insulator-semiconductor(MIS) structure fabricated with the $NbO_x$ films and the x-ray photoelectron spectroscopy(XPS) results in spite of the different deposition rates. From the experimental results, the $NbO_x$ films sputtered by pulsed-DC sputtering are expected to be used in the fabrication process instead of RF sputtering.

• 한국표면공학회지
• /
• 제46권3호
• /
• pp.99-104
• /
• 2013

The simple and cost-effective microfabrication method of photosensitive glass (PSG) using metal patterning and blank exposure was proposed. Conventional photolithography for micromachining of PSG needs a costly quartz mask which has high transmittance as an optical property. However, in this study the process was improved through the combination of micro-patterned Ti thin film and blank UV exposure without quartz mask. The effect of UV exposure time as well as the DHF etching condition was investigated. UV exposure test was performed within the range from 3 min to 9 min. The color and etch result of PSG exposed for 5 min were the most clear and effective to etch more precisely, respectively. The etching results of PSG in diluted hydrofluoric acid (DHF) with a concentration of 5, 10, 15 vol% were compared. The effect on the side etch was insignificant while the etch rate was proportional as the concentration increased. 10 vol% DHF results not only high etch rate of 75 ${\mu}m/min$ also lower side etch value after PSG etching. This method facilitates the microfabrication of PSG with various patterns and high aspect ratio for applying to advanced applications.

• Corrosion Science and Technology
• /
• 제17권4호
• /
• pp.154-165
• /
• 2018

During the process of sulfur dioxide removal, flue gas desulfurization equipment provides a serious internal corrosion environment in creating sulfuric acid dew point corrosion. Therefore, the utilities must use the excellent corrosion resistance of steel desulfurization facilities in the atmosphere. Until now, the trend in developing anti-sulfuric acid steels was essentially the addition of Cu, in order to improve the corrosion resistance. The experimental alloy used in this study is Fe-0.03C-1.0Mn-0.3Si-0.15Ni-0.31Cu alloys to which Ru, Zn and Ta were added. In order to investigate the effect of $H_2SO_4$ concentration and the alloying elements, chemical and electrochemical corrosion tests were performed. In a low concentration of $H_2SO_4$ solution, the major factor affecting the corrosion rate of low alloy steels was the exchange current density for $H^+/H_2$ reaction, while in a high concentration of $H_2SO_4$ solution, the major factors were the thin and dense passive film and resulting passivation behavior. The alloying elements reducing the exchange current density in low concentration of $H_2SO_4$, and the alloying elements decreasing the passive current density in high concentration of $H_2SO_4$, together play an important role in determining the corrosion rate of Cu-bearing low alloy steels in a wide range of $H_2SO_4$ solution.

• 한국정보통신학회논문지
• /
• 제12권3호
• /
• pp.534-540
• /
• 2008

본 연구에서는 MFSFET (Metal-Ferroelectric-Semiconductor FET) 소자의 모델링을 바탕으로 적응형 학습회로를 설계하고, 그 수치적인 결과를 분석하였다. 적응형 학습회로에서 출력주파수는 MFSFET 소자의 소스-드레인 저항과 캐패시턴스에 반비례하는 특성을 보여주었다. Short pulse 수에 따른 포화드레인 전류곡선은 강유전체의 분극반전 특성과 유사함을 확인할 수 있었고, 이는 강유전체 분극이 MFSFET 소자의 드레인 전류조절에 핵심적인 요소로 작용한다는 사실을 의미한다. 다음으로 MFSFET 소자의 소스-드레인 저항으로부터 dimensionality factor와 적응형 학습회로의 펄스 수에 따른 출력주파수 변화를 분석하였다. 이 특성으로부터 입력펄스의 진행에 따라 출력펄스의 점진적인 주파수 변화를 의미하는 적응형 학습 특성을 명확하게 확인할 수 있었고, 미래 뉴럴 네트워크에서 본 회로가 뉴런의 시넵스 부분에 효과적으로 사용될 수 있음을 입증하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
• /
• pp.194.1-194.1
• /
• 2015

Transition metal dichalcogenide (TMD) with layered structure, has recently been considered as promising candidate for next-generation flexible electronic and optoelectronic devices because of its superior electrical, optical, and mechanical properties.[1] Scalability of thickness down to a monolayer and van der Waals expitaxial structure without surface dangling bonds (consequently, native oxides) make TMD-based thin film transistors (TFTs) that are immune to the short channel effect (SCE) and provide very high field effect mobility (${\sim}200cm^2/V-sec$ that is comparable to the universal mobility of Si), respectively.[2] In addition, an excellent photo-detector with a wide spectral range from ultraviolet (UV) to close infrared (IR) is achievable with using $WSe_2$, since its energy bandgap varies between 1.2 eV (bulk) and 1.8 eV (monolayer), depending on layer thickness.[3] However, one of the critical issues that hinders the successful integration of $WSe_2$ electronic and optoelectronic devices is the lack of a reliable and controllable doping method. Such a component is essential for inducing a shift in the Fermi level, which subsequently enables wide modulations of its electrical and optical properties. In this work, we demonstrate n-doping method for $WSe_2$ on poly-4-vinylphenol and poly (melamine-co-formaldehyde) (PVP/PMF) insulating layer and adjust the doping level of $WSe_2$ by controlling concentration of PMF in the PVP/PMF layer. We investigated the doping of $WSe_2$ by PVP/PMF layer in terms of electronic and optoelectronic devices using Raman spectroscopy, electrical measurements, and optical measurements.

• 한국전기전자재료학회논문지
• /
• 제22권4호
• /
• pp.342-349
• /
• 2009

This study investigated the growth characteristics of carbon nanotubes (CNTs) by changing a period of annealing time and a $C_{2}H_{2}/H_2$ flow ratio at temperature as low as $450^{\circ}C$ with inductively coupled plasma chemical vapor deposition. The 1-nm-thick Fe-Ni-Co alloy thin film served as a catalyst layer for the growth of CNTs, which was thermally evaporated on the 15-nm-thick Al underlayer deposited on the 50-nm-thick Ti diffusion barrier. The annealing at low temperature of $450^{\circ}C$ brought about almost no granulation of the catalyst layer, and the CNT growth was not affected by a period of annealing time. A study of changing the flow rate of $C_{2}H_{2}$ and $H_2$ showed that as the ratio of the $C_{2}H_{2}$ flow rate to the $H_2$ flow rate was lowered, the CNTs were grown to be longer With further decreasing the flow ratio, the length of CNTs reached the maximum and then became shorter. Under the optimized gas flow rates, we successfully synthesized CNTs with a uniform length over a 4-inch Si wafer at $450^{\circ}C$.

• 한국재료학회지
• /
• 제19권1호
• /
• pp.33-36
• /
• 2009

Inorganic-organic composite thin-film-transistors (TFTs) of ZnO nanowire/Poly(3-hexylthiophene) (P3HT) were investigated by changing the nanowire densities inside the composites. Crystalline ZnO nanowires were synthesized via an aqueous solution method at a low temperature, and the nanowire densities inside the composites were controlled by changing the ultrasonifiaction time. The channel layers were prepared with composites by spin-coating at 2000 rpm, which was followed by annealing in a vacuum at $100^{\circ}C$ for 10 hours. Au/inorganic-organic composite layer/$SiO_2$ structures were fabricated and the mobility, $I_{on}/I_{off}$ ratio, and threshold voltage were then measured to analyze the electrical characteristics of the channel layer. Compared with a P3HT TFT, the electrical properties of TFT were found to be improved after increasing the nanowire density inside the composites. The mobility of the P3HT TFT was approximately $10^{-4}cm^2/V{\cdot}s$. However, the mobility of the ZnO nanowire/P3HT composite TFT was increased by two orders compared to that of the P3HT TFT. In terms of the $I_{on}/I_{off}$ ratio, the composite device showed a two-fold increase compared to that of the P3HT TFT.