• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.276-276
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• 2011

진공증착법으로 ITO (indium-tin-oxide) 기판 위에 $AgGaSe_2$ 박막을 성장시켜 그 구조와 광학적 특성을 조사하였다. X-선 회절 분석에 의하여 살창상수는 a=5.97 ${\AA}$와 c=10.88 ${\AA}$이고, 황동광(chalcopyrite) 구조를 하고 있었으며, 그 성장 방향은 (112)방향으로 선택 성장됨을 알 수 있었다. 증착된 박막과 200~400$^{\circ}C$로 열처리한 박막의 실온에서 측정한 광학적인 에너지 띠 간격은 2.02 eV에서 2.28 eV까지 변하였다. 또한 열린회로로 구성되어 있는 시료의 표면에 광 펄스를 주입하여 표면에서 형성된 전하들의 거동을 광유기 방전 특성(PIDC) 방법을 이용하여 조사하였다. 초기전위 V0로 형성된 시료의 양단을 주행하는 운반자 농도, 전류밀도 및 전기장 효과를 관찰하여 운반자의 주행시간, 이동도 그리고 전하운반자 농도를 계산한 결과는 각각 42 ${\mu}s$~81 ${\mu}s$, $1.9{\times}10^{-1}\;cm^2/Vs$~$5.7{\times}10^{-2}\;cm^2/Vs$ 그리고 약 $6.0{\times}10^{17}/cm^3$~$2.0{\times}10^{18}/cm^3$이었으며, p-형 전도를 나타내었다. 원자 힘 현미경 실험으로 제곱평균제곱근 거칠기와 입계크기를 조사하였으며, X-선 광전자 분광실험으로 원소들의 결합상태를 관찰하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.3
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• pp.232-239
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• 2013

Thin light-active layers of the $CuInSe_2$ solar cell were prepared on Mo-coated sodalime glass substrates by one-step electrodeposition and post-annealing. The structure, morphology, and composition of $CuInSe_2$ film could be controlled by deposition parameters, such as the composition of metallic precursors, the concentration of complexing agents, and the temperature of post-annealing with elemental selenium. A dense and uniform Cu-poor $CuInSe_2$ film was successfully obtained in a range of parametric variation of electrodeposition with a constant voltage of -0.5 V vs. a Ag/AgCl reference electrode. The post-annealing of the film at high temperature above $500^{\circ}C$ induced crystallization of $CuInSe_2$ with well-developed grains. The KCN-treatment of the annealed $CuInSe_2$ films further induced Cu-poor $CuInSe_2$ films without secondary phases, such as $Cu_2Se$. The structure, morphology, and composition of $CuInSe_2$ films were compared with respect to the conditions of electrodeposition and post-annealing using SEM, XRD, Raman, AES and EDS analysis. And the conditions for preparing device-quality $CuInSe_2$ films by electrodeposition were proposed.

• Korean Journal of Materials Research
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• v.17 no.8
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• pp.397-401
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• 2007

Fe based SOFC(Solid Oxide Fuel Cell) interconnector was fabricated by using the spark plasma sintering process and its microstructure and mechanical properties were investigated in this study. To fabricate the interconnector, the Fe-26Cr powder was mixed with the Ag (5, 10, 20wt.%) particles. In the Fe-26Cr-Ag sintered bodies, the Ag particles were almost dispersed at the grain boundary of the Fe-26Cr. The sintered bodies have the density of 87.2-97.5%, the density increases with increasing Ag content at sintering temperature of $850^{\circ}C$. Also, the compressive yield strength increases with increasing Ag content at the same sintering temperature.

• Korean Journal of Materials Research
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• v.32 no.5
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• pp.243-248
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• 2022

This study demonstrates a different approach method to fabricate antimony selenide (Sb₂Se₃) thin-films for the solar cell applications. As-deposited Sb₂Se₃ thin-films are fabricated via electrodeposition route and, subsequently, annealed in the temperature range of 230 ~ 310℃. Cyclic voltammetry is performed to investigate the electrochemical behavior of the Sb and Se ions. The deposition potential of the Sb₂Se₃ thin films is determined to be -0.6 V vs. Ag/AgCl (in 1 M KCl), where the stoichiometric composition of Sb₂Se₃ appeared. It is found that the crystal orientations of Sb₂Se₃ thin-films are largely dependent on the annealing temperature. At an annealing temperature of 250 ℃, the Sb₂Se₃ thin-film grew most along the c-axis [(211) and/or (221)] direction, which resulted in the smooth movement of carriers, thereby increasing the carrier collection probability. Therefore, the solar cell using Sb₂Se₃ thin-film annealed at 250 ℃ exhibited significant enhancement in J_SC of 10.03 mA/cm² and a highest conversion efficiency of 0.821 % because of the preferred orientation of the Sb₂Se₃ thin film.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.353.1-353.1
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• 2016

다공성 물질은 동공의 크기에 따라 미세동공(Micropore), 메조동공(Mesopore), 거대동공(Macropore)으로 나누어 분류한다. 다공성 재료의 장점은 높은 비표면적으로써, 촉매, 센서, 연료전지 전극, 에너지 저장장치 등으로의 이용 가능성을 보여주는 연구가 활발히 보고되고 있다. 종래의 연구는 두 가지 이상의 원소로 구성된 박막을 제작한 후 전기화학적 분해법, 선택적 용해법 등 습식공정을 통해 다공성 구조체를 제작하였다. 하지만 본 연구에서는 Au, Ag 타겟과 $CH_4$ gas를 이용해 ICP-assisted reactive magnetron sputtering 장비를 활용하여 450 nm 두께의 Au-C, Ag-C 박막을 제작하였다. 이후 연속적으로 RF 250 W를 ICP antenna 에 인가하여 $O_2$ plasma dealloying 공정을 통해 탄소(Carbon) 만을 선택적으로 제거함으로써, 건식 공정만으로 Si wafer ($10{\times}10mm^2$) 기판 위에 250 ~ 300 nm 두께의 다공성 Au, Ag 박막을 제작하였다. SEM (Scanning Electron Microscopy)를 활용하여 표면, 단면 형상을 관찰해 다공성 구조를 확인하였으며, AES (Auger Electron Spectroscopy)를 통해 plasma dealloying 전 후 박막의 조성변화를 관찰하였다. 따라서 plasma dealloying 공정으로 제작된 다공성 Au, Ag 박막은 기존의 습식 공정 대비 청결하고 신속한 공정이 가능하며 높은 재현성을 통해 위의 적용분야에 보다 쉽게 사용될 수 있을 것으로 기대된다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.11.2-11.2
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• 2009

Au-Ag 합금 박막에서 화학적으로 덜 안정한 Ag를 선택적으로 에칭하는 dealloying 기법을 통하여 crack-free 나노기공 gold 박막을 Si 기판에 제조하였다. Au-Ag 합금 박막은 두 가지 방법을 이용하였다: 1) thermal 또는 electron beam 증착법을 이용하여 Au 와 Ag 다층 박막을 Si 기판에 증착시킨 후 열처리를 통한 합금 박막제조; 2) co-thermal 증착법을 이용하여 Au-Ag 합금박막을 Si 기판에 직접 증착. Crack-free 나노기공 gold 박막 제조에 적합한 합금조성을 얻기 위하여 증착 속도, 열처리조건, dealloying 조건등을 조절하였다. Perchloric acid, HClO4 전해질을 이용한 전기화학적 dealloying을 통하여 crack-free 나노기공 gold 박막을 제조하였고, 기공크기를 조절할 수 있었다. 이에 더하여, electrophoretic 방법을 이용하여 나노기공 gold와 semiconductive 양자점 (CdTe 또는 CdSe)의 나노복합박막을 형성시킨 후 특성을 분석하였다.

• Journal of the Korean Chemical Society
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• v.20 no.4
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• pp.280-289
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• 1976

The silver selenide electrode has been prepared and its properties as an indicating electrode for silver ion have been investigated. Epoxy resin was used as a filler of silver selenide electrode. Silver metal plate was directly connected with the membrane of the electrode and the silver paste was used as its binder. The sintered electrode was more sensitive and stable than the pressed electrode, and the silver selenide electrode more sensitive than the silver sulfide electrode to silver ion. The linear relationship between the electrode potential and logarithmic concentration of silver ion has been observed down to 10-6 M for the electrode. Several heavy metal ions except mercuric ion did not interfere this linearity, but halide, cyanide, and thiocyanate ions did intensively interfere owing to the formation of silver compounds and complexes. This electrode has been applied to the potentiometric titration for determining halide ion. It is concluded that interferences from ,$CN^-, SCN^-, S^-, I^-, Br^-, Cl^- and Hg^{2+}$ ions are detrimental to the practical use of the electrodes for measuring pAg.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.44-51
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• 2013

For preparing a device-quality $CuInSe_2$ (CISe) light-absorbing layer by single-bath electrodeposition for a superstrate-type CISe cell, morphological properties of the CISe layers were investigated by varying concentrations of sulfamic acid and potassium biphthalate, complexing/buffering agents. CISe films were grown on an $In_2Se_3$ film by applying a constant voltage of -0.5V versus Ag/AgCl for 90 min in a solution with precursors of $CuCl_2$, $InCl_3$, and $SeO_2$, and a KCl electrolyte. A dense and smooth layer of CISe could be obtained with a solution containing both sulfamic acid and potassium biphthalate in a narrow concentration range of combination. A CISe layer prepared on the $In_2Se_3$ film with proper concentrations of complexing/buffering agents exhibited thickness of $1.6{\sim}1.8{\mu}m$ with few undesirable secondary phases. On the other hand, when the bath solution did not contain either sulfamic acid or potassium biphthalate, a CISe film appeared to contain undesirable flake-shape $Cu_{2-x}Se$ phases or sparse pores in the upper part of film.

• Bulletin of the Korean Chemical Society
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• v.15 no.11
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• pp.940-944
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• 1994

The crystal structure of an ethylene sorption complex of dehydrated $Ag_{12}-A $reacted with bromine vapor has determined by single-crystal X-ray diffraction techniques in the cubic space group of Pm3m at 22(l)$^{\circ}$C (a=12.180(2) ${\AA}$). The crystal was prepared by dehydration of $Ag_{12}$-A at 400 $^{\circ}$C and $2 {\times} l0^{-6}$ Torr for 2 days, followed by exposure to 200 Torr of ethylene gas at 24(l) $^{\circ}$C for 1 hr. After the ethylene gas was evacuated for 1 hr, the crystal was exposed to 180 Torr of bromine vapor at 24(l) $^{\circ}$C for 1.5 h. The structure was refined to the final error indices, $R_1=0.066\;and\;R_2$ (weighted)=0.055, using 137 independent reflections for which I>3${\sigma}$I. About 55% of the sodalite unit contain two 6-ring $Ag^+$ ions and the remaining 45% contain $Ag_6$ molecules complexed to 2 $Ag^+$ ions at 6-ring sites to give $(Ag^+)_2(Ag_6).$ Upon sorption of ethylene, 4.75 ethylene molecules were sorbed per unit cell and of these, only 1.25 ethylene molecules were brominated by treatment of dibromine because of the limitation of the available space for the reaction products in the large cavity. In the large cavity, each of 3.5 $Ag^+$ ions forms a lateral ${\pi}$ complex with an ethylene molecule. About 2.5 8-ring $Ag^+$ ions per unit cell interact with 1.25 1,2-dibromoethane and each of ca. 1.25 6-ring $Ag^+$ ions also interacts with one of bromine atoms of 1,2-dibromoethane. Each bromine atom approaches a carbon atom with C-Br(l)=2.07(20) ${\AA}$ and C-Br(2)=2.07(10) ${\AA}$, respectively.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1068-1070
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• 2004