• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.953-956
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• 2009

We have investigated the effect of light on amorphous silicon thin film transistors based photo-sensor applications. We have analyzed the instability caused by electrical gate bias stresses under the light illumination and the effect of photo-induced quasi-annealing on the instability. Threshold voltage ($V_{TH}$) under the negative gate bias stress with light illumination was more decreased than that under the negative gate bias stress without light illumination even though $V_{TH}$ caused by the light-induced stress without negative gate bias was shifted positively. These results are because the increase of carrier density in a channel region caused by the light illumination has the enhanced effect on the instability caused by negative gate bias stress. The prolonged light illumination led to the recovery of shifted VTH caused by negative gate bias stress under the light illumination due to the recombination of trapped hole charges.

• Journal of the Korean Solar Energy Society
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• v.38 no.1
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• pp.37-44
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• 2018

Solar panels are modules made up of many cells, like the N-type monosilicon, P-type monosilicon, P-type multisilicon, amorphous thin-film silicon, and CIGS solar cells. An efficient photovoltaic (PV) power is important to use to determine what kind of cell types are used because residential solar systems receive attention. In this study, we used 3-type solar panels - such as N-type monosilicon, P-type monosilicon, and CIGS solar cells - to investigate what kind of solar panel on a house or building performs the best. PV systems were composed of 3-type solar panels on the roof with each ~1.8 kW nominal power. N-type monosilicon solar panel resulted in the best power generation when monitored. Capacity Utilization Factor (CUF) and Performance Ratio (PR) of the N-type Si solar panel were 14.6% and 75% respectively. In comparison, N-type monosilicon and CIGS solar panels showed higher performance in power generation than P-type monosilicon solar power with increasing solar irradiance.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1303-1304
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• 2006

본 연구에서는 ICP-CVD (inductively coupled plasma chemical vapor deposition)를 이용해 미세결정 실리콘 (nanocrystalline silicon thin film transistor, ns-Si TFT) 초기 성장 단계에 발생하는 비정질의 Incubation layer를 줄이기 위한 실험을 수행하였다. ICP-CVD를 사용하여 증착한 Si-rich $SiN_x$ Seed layer 상의 미세절정 실리콘의 성막조건을 알아보고 특성을 평가하였다. 미세결정 실리콘 박막은 Raman Spectroscopy를 이용해 분석하였다. 미세결정 실리콘의 초기 성장 단계에 발생하는 비정질 Incubation layer를 줄이기 위하여 Si-rich $SiN_x$를 Seed layer로 사용하는 것이 효과적임을 확인하였다. 또한 Si-rich $SiN_x$ 위에서의 미세결정 실리콘 표면 형태와 Seed 성장 기회의 관계를 알아보았다. 높은 전압의 수소 플라즈마 처리는 Seed 성장 기회를 늘이고, 박막의 결정화도를 높임을 확인하였다. 얇은 Incubation layer를 가지는 35nm 이하 두께의 미세결정 실리콘이 성공적으로 증착되었다. 본 연구 결과는 bottom 게이트 방식 박막 트랜지스터에 증착되는 미세결정 실리콘의 전기적 특성 향상에 유용할 것으로 판단된다.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1971-1973
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• 2005

We fabricated an alumina membrane with nano-sized pore array by anodic oxidation using the thin film aluminum deposited on silicon wafer. It is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. The nano-sized pores with diameter of $60{\sim}120nm$ was obtained by $40{\sim}80$ voltage. The pore widening process was employed for obtaining the flat surface because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of rough surface. Finally, the sample was immersed to the phosphoric acid with 0.1M concentration to etching the barrier layer. The sample will be applied to electronic sensors, field emission display, and template for nano- structure.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1598-1600
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• 2003

Microcrystalline silicon(c-Si:H) thin-film solar cells are prepared with intrinsic Si-layer by hot wire CVD. The operating parameters of solar cells are strongly affected by the filament temperature ($T_f$) during intrinsic layer. Jsc and efficiency abruptly decreases with elevated $T_f$ to $1400^{\circ}C$. This deterioration of solar cell parameters are resulted from increase of crystalline volume fraction and corresponding defect density at high $T_f$ The heater temperature ($T_h$) are also critical parameter that controls device operations. Solar cells prepared at low $T_h$ (<$200^{\circ}C$) shows a similar operating properties with devices prepared at high $T_f$, i.e. low Jsc, Voc and efficiency. The origins for this result, however, are different with that of inferior device performances at high $T_f$. In addition the phase transition of the silicon films occurs at different silane concentration (SC) by varying filament temperature, by which highest efficiency with SC vanes with $T_f$.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.151-151
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• 2010

In this paper, the electrically properties of nonvolatile memory (NVM) using multi-stacks gate insulators of oxide-nitride-oxynitride (ONOn) and active layer of the low temperature polycrystalline silicon (LTPS) were investigated. From hydrogenated amorphous silicon (a-Si:H), the LTPS thin films with high crystalline fraction of 96% and low surface's roughness of 1.28 nm were fabricated by the metal induced crystallization (MIC) with annealing conditions of $650^{\circ}C$ for 5 hours on glass substrates. The LTPS thin film transistor (TFT) or the NVM obtains a field effect mobility of ($\mu_{FE}$) $10\;cm^2/V{\cdot}s$, threshold voltage ($V_{TH}$) of -3.5V. The results demonstrated that the NVM has a memory window of 1.6 V with a programming and erasing (P/E) voltage of -14 V and 14 V in 1 ms. Moreover, retention properties of the memory was determined exceed 80% after 10 years. Therefore, the LTPS fabricated by the MIC became a potential material for NVM application which employed for the system integration of the panel display.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.193-193
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• 2013

실리콘 박막 태양전지는 광 흡수층에서 형성된 정공과 전자를 효과적으로 분리하기 위해 p형과 n형으로 도핑된 층을 형성하는 p-i-n구조를 갖게 된다. 이러한 도핑 층을 형성하기 위해 B2H6와 PH3와 같은 독성 가스를 사용하기 때문에, 공정 안정성과 환경적인 이슈가 대두된다. 또한 도핑은 추가적으로 실리콘 박막 태양전지의 안정화 효율을 지속적으로 저하시키는 요인이 된다. 이러한 문제점을 개선하기 위하여, 창층으로 MoO3, V2O5, WO3 등과 같이 높은 일함수를 갖는 전이금속 산화물을 사용하고, 광 흡수층으로 i-Si:H을, 후면 전극으로 낮은 일함수를 나타내는 LiF/Al을 사용하였다. 전이금속 산화물과 LiF/Al의 큰 일함수 차이에 의해서 흡수층인 i-Si:H 에서 생성된 캐리어들은 효과적으로 분리되고 수집이 된다. 금속 산화물은 스퍼터링 공정에 의하여 이루어졌으며, 스퍼터링 공정조건에 따라 산화도가 조절되며, 이러한 산화도에 따라 태양전지의 셀 특성이 결정된다. 도핑 층이 없는 새로운 형태의 실리콘 박막 태양전지는 기존 비정질 실리콘 박막 태양전지에 비해 높은 안정화 효율을 나타내며, 이는 도핑 층이 없기 때문에 기존 실리콘 박막 태양전지의 열화현상에 따른 효율저하가 발생하지 않는 장점을 지내고 있다.

• Korean Journal of Metals and Materials
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• v.50 no.8
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• pp.575-582
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• 2012

Medium carbon steel was aluminized by hot dipping into molten Al or Al-1 at% Si baths. After hot-dipping in these baths, a thin Al-rich topcoat and a thick alloy layer rich in $Al_5Fe_2$ formed on the surface. A small amount of FeAl and $Al_3Fe$ was incorporated in the alloy layer. Silicon from the Al-1 at% Si bath was uniformly distributed throughout the entire coating. The hot dipping increased the microhardness of the steel by about 8 times. Heating at $700-1000^{\circ}C$, however, decreased the microhardness through interdiffusion between the coating and the substrate. The oxidation at $700-1000^{\circ}C$ in air formed a thin protective ${\alpha}-Al_2O_3$ layer, which provided good oxidation resistance. Silicon was oxidized to amorphous silica, exhibiting a glassy oxide surface.

• Journal of Integrative Natural Science
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• v.14 no.1
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• pp.1-5
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• 2021

A zinc oxide thin film was made by varying the deposition time on the silicon(110) substrate by using a radio frequency sputtering time of 60 minutes, 120 minutes and 180 minutes. As a result of analyzing the grain growth surface of the ZnO₂ thin film using an X-ray diffraction apparatus, the directions of the main growth plane (002) and (103) planes of the thin film were significantly affected by the deposition time. As a result of observing the particle growth of the ZnO₂ thin film through an electron scanning microscope, it was observed that in the initial stage of deposition of the ZnO₂ thin film, an incubation time was required during which growth was stagnant, and then particle growth occurred again after a certain period of time. As a result of chemical analysis of the ZnO₂ thin film, the increase in the deposition time did not change with the amount of oxygen in the ZnO₂ thin film, but a change in the composition of Zn was observed, indicating that the deposition time of the thin film had an effect on the Zn component in the thin film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.754-759
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• 2013

Aluminum oxide($Al_2O_3$) film deposited by atomic layer deposition (ALD) is known to supply excellent surface passivation properties on crystalline Si surfaces. Since $Al_2O_3$ has fixed negative charge, it forms effective surface passivation by field effect passivation on the rear side in p-type silicon solar cell. However, $Al_2O_3$ layer formed by ALD process needs very long process time, which is not applicable in mass production of silicon solar cells. In this paper, plasma-assisted ALD(PA-ALD) was applied to form $Al_2O_3$ to reduce the process time. $Al_2O_3$ synthesized by ALD on c-Si (100) wafers contains a very thin interfacial $SiO_2$ layer, which was confirmed by FTIR and TEM. To improve passivation quality of $Al_2O_3$ layer, the deposition temperature was changed in range of $150{\sim}350^{\circ}C$, then the annealing temperature and time were varied. As a result, the silicon wafer with aluminum oxide film formed in $250^{\circ}C$, $400^{\circ}C$ and 10 min for the deposition temperature, the annealing temperature and time, respectively, showed the best lifetime of 1.6ms. We also observed blistering with nanometer size during firing of $Al_2O_3$ deposited on p-type silicon.