• Korean Journal of Materials Research
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• v.23 no.1
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• pp.7-12
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• 2013

The $Cu_2ZnSnS_4$ (CZTS) thin film solar cell is a candidate next generation thin film solar cell. For the application of an absorption layer in solar cells, CZTS thin films were deposited by pulsed laser deposition (PLD) at substrate temperature of $300^{\circ}C$ without post annealing process. Deposition time was carefully adjusted as the main experimental variable. Regardless of deposition time, single phase CZTS thin films are obtained with no existence of secondary phases. Irregularly-shaped grains are densely formed on the surface of CZTS thin films. With increasing deposition time, the grain size increases and the thickness of the CZTS thin films increases from 0.16 to $1{\mu}m$. The variation of the surface morphology and thickness of the CZTS thin films depends on the deposition time. The stoichiometry of all CZTS thin films shows a Cu-rich and S-poor state. Sn content gradually increases as deposition time increases. Secondary ion mass spectrometry was carried out to evaluate the elemental depth distribution in CZTS thin films. The optimal deposition time to grow CZTS thin films is 150 min. In this study, we show the effect of deposition time on the structural properties of CZTS thin film deposited on soda lime glass (SLG) substrate using PLD. We present a comprehensive evaluation of CZTS thin films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.75-80
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• 2005

In this thesis, We Fabricated Cu thin films of 1000 $\AA$, 3000 $\AA$, and 6000 $\AA$ thickness on the single crystal sapphire, polycrystal alumina, and amorphous slide glass substrates deposited by electron beam evaporation(EBE) method. We investigated properties of resistivity and adhesion of these Cu thin films under various conditions, substrate temperature(room temperature, 10$0^{\circ}C$, 20$0^{\circ}C$ under vacuum) and annealing temperatures(400 $^{\circ}C$, 600 $^{\circ}C$ for 30 min after the deposition). We found that these adhesion was increased in order of slide glass, sapphire, and alumina. The adhesion of the Cu thin films on alumina was high value about 4 times, compared with that of the Cu thin films on slide glass. We found that these resistivities were decreased with increasing substrate temperature and thin film thickness. The resistivity(2.05 $\mu$Ω\ulcornercm) of the Cu thin films with 6000 $\AA$ thickness at 200 $^{\circ}C$ on the slide glass was low value, compared with that of aluminum(2.66 $\mu$Ω\ulcornercm).

• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.18-20
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• 2016

Transparent and conducting IGZO thin films were deposited by RF magnetron sputtering on thin Cu coated glass substrates to investigate the effect of a Cu buffer layer on the structural, optical, and electrical film properties. Although X-ray diffraction (XRD) analysis revealed that both the IGZO single layer and IGZO/Cu bi-layered films were in the amorphous phase, the IGZO/Cu films showed a lower resistivity of 5.7×10⁻⁴ Ωcm due to the increased mobility and high carrier concentration. The decreased optical transmittance of the IGZO/Cu films was also attributed to a one order of magnitude higher carrier concentration than the IGZO films. From the observed results, the thin Cu layer is postulated to be an effective buffer film that can enhance the opto-electrical performance of the IGZO films in transparent thin film transistors.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.3
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• pp.193-199
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• 2013

In this work, thin film type Cu/ZnO nanostructure catalysts were fabricated by several synthetic routes in order to maximize the performance of the micro reforming system. For this work, various Cu/ZnO nanostructure catalysts could be synthesized by means of four approaches which are chemical vapor method, wet solution method and their hybrid method. The reforming performance of these as-synthetic catalysts was evaluated as compared to the conventional catalysts. Among the as-synthetic nanostructures, sphere type catalysts with specific surface of $18.6m^2/g$ showed the best performance of hydrogen production rate of 30ml/min at the feed rate of 0.2ml/min. This work will give the first insight on thin film type Cu/ZnO nanostructure catalyst for micro reforming system for hydrogen production of portable electronic systems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.911-914
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• 2010

In this paper, the $CuInSe_2$ thin film was prepared by using co-evaporation method in four different substrate temperatures $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$ and $400^{\circ}C$. When the substrate temperature was at $200^{\circ}C$ and $300^{\circ}C$, the single-phase $CuInSe_2$ was crystallized. As the temperature increased, it was shown that the thickness of the thin film was decreased with increment of the hall coefficient. When the sample was prepared at $200^{\circ}C$ of the subsrate temperature, the values of band gap energy (Eg), sheet resister and resistivity were measured 0.99 eV, $89.82\;{\Omega}/{\square}$ and $103{\times}10^{-4}\;{\Omega}{\cdot}cm$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.119-122
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• 2006

Process variables for manufacturing the $CuInSe_2$ thin film were established in order to clarify optimum conditions for growth of the thin film depending upon process conditions (substrate temperature, sputtering pressure, DC/RF Power), and then by changing a number of vapor deposition conditions and Annealing conditions variously, structural and electrical characteristics were measured. Thereby, optimum process variables were derived. For the manufacture of the $CuInSe_2$, Cu, In and Se were vapor-deposited in the named order. Among them, Cu and In were vapor-deposited by using the sputtering method in consideration of their adhesive force to the substrate, and the DC/RF power was controlled so that the composition of Cu and In might be 1:1, while the surface temperature having an effect on the quality of the thin film was changed from 100[$^{\circ}C$] to 300[$^{\circ}C$] at intervals of 50[$^{\circ}C$].

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.594-599
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• 2007

[ $CulnS_2$ ] thin films were synthesized by sulfurization of Cu/In Stacked elemental layer deposited onto glass Substrates by vacuum furnace annealing at temperature $200^{\circ}C$. And structural and electrical properties were measured in order to certify optimum conditions for growth of the ternary compound semiconductor $CuInS_2$ thin films with non-stoichiometry composition. $CuInS_2$ thin film was well made at the annealed $200^{\circ}C$ of SLG/Cu/In/S stacked elemental layer which was prepared by thermal evaporator, and chemical composition of the thin film was analyzed nearly as the proportion of 1 : 1 : 2. Physical properties of the thin film were investigated at various fabrication conditions substrate temperature, annealing and temperature, annealing time by XRD, FE-SEM and Hall measurement system. The compositional deviations from the ideal chemical formula for $200^{\circ}C$ material can be conveniently described by non-molecularity$({\Delta}x=[Cu/In]-1)$ and non-stoichiometry $({\Delta}y=[{2S/(Cu+3In)}-1])$. The variation of ${\Delta}x$ would lead to the formation of equal number of donor and accepters and the films would behave like a compensated material. The ${\Delta}y$ parameter is related to the electronic defects and would determine the type of the majority charge carriers. Films with ${\Delta}y>0$ would behave as p-type material while ${\Delta}y<0$ would show n-type conductivity. At the sane time, carrier concentration, hall mobility and resistivity of the thin films was $9.10568{\times}10^{17}cm^{-3},\;312.502cm^2/V{\cdot}s\;and\;2.36{\times}10^{-2}\;{\Omega}{\cdot}cm$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.49-51
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• 2006

Ternary chalcopyrite $CuInS_2$ thin film material is very promising for photovoltaic. Power generation because of its excellent optical and semiconductor properties, $CuInS_2$ thin films were performed from S/In/Cu/SLG stacked elemental layer (SEL) method with post annealing treatment. $CuInS_2$ thin films were appeared from 0.84 to 1.27 of Cu/In composition ratio and sulfur composition ratios of $CuInS_2$ thin films fabricated. Analysis of the optical energy band gap of $CuInS_2$ value of l.5eV interior and exterior.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.99.1-99.1
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• 2010

Many efforts on the surface sulfurization of $Cu(InGa)Se_2$ (CIGS)thin films have been reported as techniques to improve CIGS solar cell performance. We have investigated the sulfurization technique using the sulfur vapor. The co-evaporated $Cu(In,Ga)Se_2$ tin film was used for sulfurization. A thin $Cu(In,Ga)(S,Se)_2$ layer was grown on the surface of the CIGS thin film after high-temperature annealing in sulfur vapor. The structural and compositional properties of the thin films were studied by XRD, EDS and AES analysis. The obtained results revealed that the surface modification technique is promising method to S incorporated into CIGS absorber.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.86.2-86.2
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• 2015

Cu2ZnSn(S,Se)4 thin film solar cells have been fabricated using sputtered Cu/Sn/Zn metallic precursors on Mo coated sodalime glass substrate without using a toxic H2Se and H2S atmosphere. Cu/Sn/Zn metallic precursors with various thicknesses were prepared using DC magnetron sputtering process at room temperature. As-deposited metallic precursors were sulfo-selenized inside a graphite box containing S and Se pellets using rapid thermal processing furnace at various sulfur to selenium (S/Se) compositional ratio. Thin film solar cells were fabricated after sulfo-selenization process using a 65 nm CdS buffer, a 40 nm intrinsic ZnO, a 400 nm Al doped ZnO, and Al/Ni top metal contact. Effects of sulfur to selenium (S/Se) compositional ratio on the microstructure, crystallinity, electrical properties, and cell efficiencies have been studied using X-ray diffraction, Raman spectroscopy, field emission scanning electron microscope, I-V measurement system, solar simulator, quantum efficiency measurement system, and time resolved photoluminescence spectrometer. Our fabricated Cu2ZnSn(S,Se)4 thin film solar cell shows the best conversion efficiency of 9.24 % (Voc : 454.6 mV, Jsc : 32.14 mA/cm2, FF : 63.29 %, and active area : 0.433 cm2), which is the highest efficiency among Cu2ZnSn(S,Se)4 thin film solar cells prepared using sputter deposited metallic precursors and without using a toxic H2Se gas. Details about other experimental results will be discussed during the presentation.