• 한국재료학회지
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• 제28권12호
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• pp.748-757
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• 2018

Inorganic semiconductor compounds, e.g., CIGS and CZTS, are promising materials for thin film solar cells because of their high light absorption coefficient and stability. Research on thin film solar cells using this compound has made remarkable progress in the last two decades. Vacuum-based processes, e.g., co-evaporation and sputtering, are well established to obtain high-efficiency CIGS and/or CZTS thin film solar cells with over 20 % of power conversion. However, because the vacuum-based processes need high cost equipment, they pose technological barriers to producing low-cost and large area photovoltaic cells. Recently, non-vacuum based processes, for example the solution/nanoparticle precursor process, the electrodeposition method, or the polymer-capped precursors process, have been intensively studied to reduce capital expenditure. Lately, over 17 % of energy conversion efficiency has been reported by solution precursors methods in CIGS solar cells. This article reviews the status of non-vacuum techniques that are used to fabricate CIGS and CZTS thin films solar cells.

• 소성∙가공
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• 제21권3호
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• pp.195-201
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• 2012

A vacuum ladling die casting system is suggested as a means to obtain a high vacuum level. A high vacuum of 17.8 mmHg is obtained by sealing the inner space of the mould. The sample product is a rear-head housing for an auto-compressor, and the die-casting with 6-cavities was conducted. The flow analysis shows that the filling speed during vacuum ladling is faster than for a non-vacuum system. The air holes in the sample product were too small to be seen with the naked eye in X-ray films. Density tests show that the high vacuum ladling system reduces the internal porosity as much as 57.8% when compared to the non-vacuum system. A defective rate of only 0.17% was found from leak testing. The results of this research prove that the high vacuum die-casting process is useful for manufacturing of aluminium components under high internal pressure.

• Applied Science and Convergence Technology
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• 제23권6호
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• pp.309-316
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• 2014

A large particle accelerator requires an ultrahigh vacuum (UHV) system of average pressure under $1{\times}10^{-7}$ Pa for mitigating the impact of beam scattering from the residual gas molecules. The surface inside the beam ducts should be controlled with an extremely low thermal outgassing rate under $1{\times}10^{-9}Pa{\cdot}m^3/(s{\cdot}m^2)$ for the sake of the insufficient pumping speed. To fulfil the requirements, the aluminum alloys were adopted as the materials of the beam ducts for large accelerator that thanks to the good features of higher thermal conductivity, non-radioactivity, non-magnetism, precise machining capability, et al. To put the aluminum into the large accelerator vacuum systems, several key technologies have been developed will be introduced. The concepts contain the precise computer numerical control (CNC) machining process for the large aluminum ducts and parts in pure alcohol and in an oil-free environment, surface cleaning with ozonized water, stringent welding process control manually or automatically to form a large sector of aluminum ducts, ex-situ baking process to reach UHV and sealed for transportation and installation, UHV pumping with the sputtering ion pumps and the non-evaporable getters (NEG), et al. The developed UHV technologies have been applied to the 3 GeV Taiwan Photon Source (TPS) and revealed good results as the expectation. The problems of leakage encountered during the assembling were most associated with the vacuum baking which result in the consequent trouble shootings and more times of baking. Then the installation of the well-sealed UHV systems is recommended.

• Transactions on Electrical and Electronic Materials
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• 제17권5호
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• pp.306-309
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• 2016

The Cs₃Sb photocathode was formed by non-vacuum process technology. An in-situ vacuum device was fabricated successively with flat cesium antimonide photocathode emitters fabricated in a process chamber. The electrical properties of the device were characterized. Electron emission from the devices was induced by photoemitted electrons, which were accelerated by an anode electric field that was shielded from the photoemitter surface. The electrical characteristics of the devices were investigated by measuring the anode current as a function of device operation times with respect to applied anode voltages. Planar blue LED light with a 450 nm wavelength was used as an excitation source. The results showed that the cesium antimonide photocathode emitter has the potential of long lifetime with stable electron emission characteristics in panel devices. These features demonstrate that the cesium antimony photocathodes produced by non-vacuum processing technology is suitable for flat cathodes in panel device applications.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.441-443
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• 2008

A non-vacuum process for fabrication of $CuInSe_2$ (CIS) absorber layer from the corresponding Cu, In solution precursors was described. Cu, In solution precursors was prepared by a room temperature colloidal route by reacting the starting materials $Cu(NO_3)_2$, $InCl_3$ and methanol. The Cu, In solution precursors were mixed with ethylcellulose as organic binder material for the rheology of the mixture to be adjusted for the doctor blade method. After depositing the mixture of Cu, In solution with binder on Mo/glass substrate, the samples were preheated on the hot plate in air to evaporate remaining solvents and to burn the organic binder material. Subsequently, the resultant CI/Mo/glass sample was selenized in Se evaporation in order to get a solar cell applicable dense CIS absorber layer. The CIS absorber layer selenized at $530^{\circ}C$ substrate temperature for 30 min with various Se gas evaporation temperature was characterized by XRD, SEM, EDS.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.19-22
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• 2009

A non-vacuum process for fabrication of $CuIn_xGa_{1-x}Se_2$ (CIGS) absorber layer from the corresponing Cu, In, Ga solution precursors was described. Cu, In, Ga precursor solution was prepared by a room temperature colloidal route by reacting the starting materials $Cu(NO_3)_2$, $InCl_3$, $Ga(NO_3)$ and methanol. The Cu, In, Ga precursor solution was mixed with ethylcellulose as organic binder material for the rheology of the mixture to be adjusted for the doctor blade method. After depositing the mixture of Cu, In, Ga solution with binder on Mo/glass substrate, the samples were preheated on the hot plate in air to evaporate remaining solvents and to burn the organic binder material. Subsequently, the resultant CIG/Mo/glass sample was selenized in Se evaporation in order to get a solar cell applicable dense CIGS absorber layer. The CIGS absorber layer selenized at $530^{\circ}C$ substrate temperature for 1h with various metal organic ratio.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.222-224
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• 2006

A non-vacuum process for $Cu(In,Ga)Se_2$ (CIGS) thin film solar cells from nanoparticle precursors was described in this work CIGS nanoparticle precursors was prepared by a low temperature colloidal route by reacting the starting materials $(CuI,\;InI_3,\;GaI_3\;and\;Na_2Se)$ in organic solvents, by which fine CIGS nanoparticles of about 20nm in diameter were obtained. The nanoparticle precursors were mixed with organic binder material for the rheology of the mixture to be adjusted for the doctor blade method. After depositing the mixture of CIGS with binder on Mo/glass substrate, the samples were preheated on the hot plate in air to evaporate remaining solvents ud to burn the organic binder material. Subsequently, the resultant (porous) CIGS/Mo/glass simple was selenized in a two-zone Rapid Thermal Process (RTP) furnace in order to get a solar ceil applicable dense CIGS absorber layer. Complete solar cell structure was obtained by depositing. The other layers including CdS buffer layer, ZnO window layer and Al electrodes by conventional methods. The resultant solar cell showed a conversion efficiency of 0.5%.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.473-473
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• 2010

Plasma is widely used in various commercial etchers and chemical vapor deposition. Unfortunately, real-time plasma process monitoring is still difficult. Some methods of plasma diagnosis is improved, however, it is possible for real-time plasma diagnosis to use non-intrusive probe only. In this research, the object is to investigate the suitability of using impedance analysis and optical emission spectroscopy (OES) for real-time plasma process monitoring. It is assumed that plasma system is a equivalent circuit. Therefore, V-I probe is used for measuring impedance, which can be a new non-intrusive probe for plasma diagnosis. From impedance data, we tried to analyse physical properties of plasma. And OES, the other method of plasma diagnosis, is a typical non-intrusive probe for analyzing chemical properties. The amount of the OES data is typically large, so this poses a difficulty in extracting relevant information. To solve this problem, principal component analysis (PCA) can be used. For fundamental information, Ar plasma and $O_2$ plasma are used in this experiment. This method can be applied to real-time endpoint and fault detections.

• Journal of Advanced Marine Engineering and Technology
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• 제41권3호
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• pp.182-190
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• 2017

모든 액체는 소량의 기체성분들이 녹아있으며, 액체에 용해되는 기체의 양은 액체에 작용하는 주위압력에 기여하는 각 기체성분의 분압에 비례한다는 헨리의 법칙을 따른다. 따라서 다단증발식 해수담수화설비의 경우, 각 증발단의 운전온도와 압력은 다르며, 이 운전조건에 비례하여 해수에 용해되어 있던 기체들이 증발과정에서 방출되는데 주성분은 불응축기체인 이산화탄소, 질소, 산소 및 아르곤이다. 대류열전달의 입장에서는 불응축기체는 증발증기를 응축시키는 냉각기의 성능을 저하시키는 주요한 원인이기 때문에 증발과정에서 방출되는 불응축기체의 평가는 증발식 해수담수화설비에서 중요한 설계인자 중의 한가지이다. 증발식 해수담수화공정의 경우, 대부분의 증발기는 진공압력으로 유지되기 때문에 진공유지장치의 설계를 위해서는 증발과정에서 해수로부터 방출되는 불응축기체의 방출량을 평가하는 것이 매우 중요다. 본 연구는 불응축기체의 방출량을 정량적으로 계산하기 위해 수행하였으며, 연구결과에 따르면 불응축가스의 방출량은 후단으로 갈수록 감소하며, 담수생산량에 비례함을 알 수 있었다.

• 센서학회지
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• 제24권4호
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• pp.215-218
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• 2015

As several innovative technologies for flexible electric devices are being realized, demand for in-situ strain monitoring for flexible electric devices is being emphasized. Because flexible devices are commonly influenced by substrate strain, suitable strain sensors for flexible devices are essential for the sophisticated maneuvering of flexible devices. In this study, a flexible strain sensor based on an Ag electrode is prepared on a polyimide substrate using the LDW (laser direct writing) process. In this process, first, the Ag nanoparticles are coated on the substrate and selectively sintered using a focused laser. Because of the advantages of the LDW process (such as being mask-less, using low temperatures, and having non-vacuum characteristics), the entire fabrication process has been dramatically simplified; as a final outcome, a highly reliable strain sensor has been fabricated. Using this strain sensor, various strain conditions that arise from different bending radii can be detected by measuring real-time electrical signals.