• 한국재료학회지
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• 제11권4호
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• pp.283-289
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• 2001

50/50 vol% LSM-YSZ (La$_{1-x}$Sr$_{x}$MnO$_3$-yttria stabilized zirconia)의 복합공기극이 콜로이드 증착법에 의해 연마된 YSZ 전해질상에 증착되었다. 그 전극 특성은 주사전자현미경, X선회절과 임피던스 분석기에 의해 연구되어졌다. 90$0^{\circ}C$에서 공기/LSM -YSZ/YSZ/Pt/공기 셀에 대해 측정된 전형적인 임피던스 스펙트럼들은 2개의 불완전한 호(depressed arc)로 구성되었다. LSM 전극에 대한 YSZ의 첨가는 전극내의 삼상계(TPB) 영역을 증가시켰으며, 이것이 LSM-YSZ 복합공기극의 비저항을 감소시켰다. 또한 전해질 표면의 불순물 제거와 TPB 길이의 증가를 위한 전해질 표면연마는 공기극의 비저항을 훨씬 더 감소시켰다. LSM-YSZ 공기극의 비저항은 작동온도, 공기극의 조성과 입자크기, 인가전류 및 전해질의 표면거칠기에 의해 큰 영향을 받았다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.331-334
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• 2003

Photovoltaics is considered as one of the most promising new energy technology, because its energy source is omni present, pollution-free and inexhaustive. It is agreed that these solar cells must be thin film type because thin film process is cost-efficive in the fact that it uses much less raw materials and can be continuous. The defect chalcopyrite material $CuIn_3Se_5$ has been identified as playing an essential role in efficient photovoltaic action in $CuInSe_2$-based devicesm It has been reported to be of n-type conductivity, forming a p-n junction with its p-type counterpart $CuInSe_2$. Because the most efficient cells consist of the $Cu(In,Ga)Se_2$ quarternary, knowledge of some physical properties of the Ga-containing defect chalcopyrite $Cu(In,Ga)_3Se_5$ may help us better understand the junction phenomena in such devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1555-1558
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• 2002

This paper presents deposition and characterizations of microcrystalline silicon(${\mu}c$-Si:H) films prepared by hot wire chemical vapor deposition at substrate temperature below $300^{\circ}C$. The $SiH_4$ Concentration$[F(SiH_4)/F(SiH_4)+F(H_2)]$ is critical parameter for the formation of Si films with microcrystalline phase. At 6% of silane concentration, deposited intrinsic ${\mu}c$-Si:H films shows sufficiently low dark conductivity and high photo sensitivity for solar cell applications. P-type ${\mu}c$-S:H films deposited by Hot-Wire CVD also shows good electrical properties by varying the rate of $B_2H_6$ to $SiH_4$ gas. The solar cells with structure of Al/nip ${\mu}c$-Si:H/TCO/glass was fabricated with sing1e chamber Hot-Wire CVD. About 3% solar efficiency was obtained and applicability of HWCVD for thin film solar cells was proven in this research.

• 한국전기전자재료학회논문지
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• 제13권9호
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• pp.751-757
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• 2000

The r.f. power effect for Pt doping is investigated on structural and electrochemical properties of amorphous vanadium oxide(V$_2$O$_{5}$) film, grown by direct current (d.c.) magnetron sputtering. Room temperature charge-discharge measurements based on a half-cell with a constant current clearly indicated that the Pt doping could improve the cyclibility of V$_2$O$_{5}$ cathode film. Using glancing angle x-ray diffraction(GXRD) and high-resolution transmission electron microscopy (HRTEM) analysis, we found that the Pt doping with 10W r.f. power induces more random amorphous structure than undoped V$_2$O$_{5}$ film. As the r.f. power of Pt target increases. large amount of Pt atoms incorporates into the amorphous V$_2$O$_{5}$ film and makes $\alpha$-PtO$_2$microcrystalline phase in the amorphous V$_2$O$_{5}$ matrix. These results suggest that the semiconducting $\alpha$-PtO$_2$ microcrystalline phase in amorphous matrix lead to a drastically faded cyclibility of 50W Pt doped V$_2$O$_{5}$ cathode film. Possible explanations are given to describe the Pt doping effect on cyclibillity of the amorphous V$_2$O$_{5}$ cathode film battery. film battery.

• 한국표면공학회지
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• 제46권4호
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• pp.168-174
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• 2013

In this study, low-cost, high-speed deposition, excellent processability, high mechanical strength and electrical conductivity, chemical stability and corrosion resistance of stainless steel to meet the obsessive-compulsive (0.1 mm or less) were selected CrN thin film. new price reduction to sputter deposition causes - the possibility of sublimation source for inductively coupled plasma Cr rods were attempts by DC bias. 0.6 Pa Ar inductively coupled plasmas of 2.4 MHz, 500 W, keeping Cr Rod DC bias power 30 W (900 V, 0.02 A) is applied, $N_2$ flow rate of 0.5, 1.0, 1.5 sccm by varying the characteristics of were analyzed. $N_2$ flow rate increases, decreases and $Cr_2N$, CrN was found to increase. In addition to corrosion resistance and contact resistance, corrosion resistance, electrical conductivity was evaluated. corrosion current density than $N_2$ 0 sccm was sure to rise in all, $N_2$ 1 sccm at $4.390{\times}10^{-7}$ (at 0.6 V) $A{\cdot}cm^{-2}$, respectively. electrical conductivity process results when $N_2$ 1 sccm 28.8 $m{\Omega}/cm^2$ with the lowest value of the contact resistance was confirmed that came out. The OES (SQ-2000) and QMS (CPM-300) using a reactive deposition process to add $N_2$ to maintain a uniform deposition rate was confirmed that.

• 전기화학회지
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• 제14권3호
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• pp.145-151
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• 2011

ZnSe는 가시광선 영역에서 넓은 밴드갭을 가지고 있는 II-VI족 화합물 반도체 소자로서 레이저 다이오드, 디스플레이 그리고 태양전지와 같은 다양한 응용분야에 적용되고 있다. 본 연구에서는 전기화학적 전착방법을 이용하여 ITO 전극상에 ZnSe 박막을 합성하여, XRD와 SEM으로 ZnSe 결정의 합성과 zinc blende 구조의 형태를 관측하였고, UV 분광기를 활용하여 밴드갭을 측정한 결과 2.76 eV이었다. 또한, 분자동역학에서 활용되는 밀도범함수 이론 (DFT, Density Functional Theory)을 도입하여 ZnSe 결정에 대한 밴드 구조의 해석을 수행하였다. Zinc blende구조를 갖는 ZnSe 결정에 대하여 LDA (Local Density Approximation), PBE (Perdew Burke Ernzerhof), 그리고 B3LYP (Becke, 3-parameter, Lee-Yang-Parr) 범함수를 이용하여 밴드구조와 상태밀도 (Density of State)를 모사하였다. 각각의 경우에 대해 에너지 밴드갭을 구한 결과, B3LYP 범함수로 해석한 경우에 실험치와 근사치인 2.65 eV의 밴드갭을 보여주었다.

• 한국재료학회지
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• 제23권12호
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• pp.680-686
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• 2013

Tungsten oxide films were prepared by an electrochemical deposition method for use as the anode in rechargeable lithium batteries. Continuous potentiostatic deposition of the film led to numerous cracks of the deposits while pulsed deposition significantly suppressed crack generation and film delamination. In particular, a crack-free dense tungsten oxide film with a thickness of ca. 210 nm was successfully created by pulsed deposition. The thickness of tungsten oxide was linearly proportional to deposition time. Compositional and structural analyses revealed that the as-prepared deposit was amorphous tungsten oxide and the heat treatment transformed it into crystalline triclinic tungsten oxide. Both the as-prepared and heat-treated samples reacted reversibly with lithium as the anode for rechargeable lithium batteries. Typical peaks for the conversion processes of tungsten oxides were observed in cyclic voltammograms, and the reversibility of the heat-treated sample exceeded that of the as-prepared one. Consistently, the cycling stability of the heat-treated sample proved to be much better than that of the as-prepared one in a galvanostatic charge/discharge experiment. These results demonstrate the feasibility of using electrolytic tungsten oxide films as the anode in rechargeable lithium batteries. However, further works are still needed to make a dense film with higher thickness and improved cycling stability for its practical use.

• Current Photovoltaic Research
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• 제6권1호
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• pp.21-26
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• 2018

Beside several advantages, the PV power generation as a clean energy source, is still below the supply level due to high power generation cost. Therefore, the interest in fabricating low-cost thin film solar cells is increasing continuously. $Cu_2O$, a low cost photovoltaic material, has a wide direct band gap of ~2.1 eV has along with the high theoretical energy conversion efficiency of about 20%. On the other hand, it has other benefits such as earth-abundance, low cost, non-toxic, high carrier mobility ($100cm^2/Vs$). In spite of these various advantages, the efficiency of $Cu_2O$ based solar cells is still significantly lower than the theoretical limit as reported in several literatures. One of the reasons behind the low efficiency of $Cu_2O$ solar cells can be the formation of CuO layer due to atmospheric surface oxidation of $Cu_2O$ absorber layer. In this work, atomic layer deposition method was used to remove the CuO layer that formed on $Cu_2O$ surface. First, $Cu_2O$ absorber layer was deposited by electrodeposition. On top of it buffer (ZnO) and TCO (AZO) layers were deposited by atomic layer deposition and rf-magnetron sputtering respectively. We fabricated the cells with a change in the deposition temperature of buffer layer ranging between $80^{\circ}C$ to $140^{\circ}C$. Finally, we compared the performance of fabricated solar cells, and studied the influence of buffer layer deposition temperature on $Cu_2O$ based solar cells by J-V and XPS measurements.

• 한국세라믹학회지
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• 제42권12호
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• pp.827-832
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• 2005

In this study, thin electrolyte layer was prepared by 8YSZ ($8mol\%$ Yttria-Stabilized Zirconia) slurry dip and sol coating onto the porous anode support in order to reduce ohmic resistance. 8YSZ polymeric sol was prepared from inorganic salt of nitrate and XRF results of xerogel powder exhibited similar results $(99.2\pm1wt\%)$ compared with standard sample (TZ-8YS, Tosoh Co.). The dense and thin YSZ film with $1{\mu}m$ thickness was synthesized by coating of 0.7M YSZ sol followed by heat-treatment at $600^{\circ}C$ for 1 h. Thin film electrolyte sintered at $1400^{\circ}C$ showed no gas leakage at the differential pressure condition of 3 atm.

• 한국재료학회지
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• 제30권2호
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• pp.68-73
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• 2020

Due to its favorable optical properties, Cu₂SnS₃ (CTS) is a promising material for thin film solar cells. Doping, which modifies the absorber properties, is one way to improve the conversion efficiency of CTS solar cells. In this work, CTS solar cells with selenium doping were fabricated on a flexible substrate using sputtering method and the effect of doping on the properties of CTS solar cells was investigated. In XRD analysis, a shift in the CTS peaks can be observed due to the doped selenium. XRF analysis confirmed the different ratios of Cu/Sn and (S+Se)/(Cu+Sn) depending on the amount of selenium doping. Selenium doping can help to lower the chemical potential of sulfur. This effectively reduces the point defects of CTS thin films. Overall improved electrical properties were observed in the CTS solar cell with a small amount of selenium doping, and a notable conversion efficiency of 1.02 % was achieved in the CTS solar cell doped with 1 at% of selenium.