• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.392.2-392.2
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• 2016

본 연구에서는 인버티드 유기 태양전지에 적용하기 위한 버퍼 하이브리드 투명 캐소드를 RF/DC magnetron 스퍼터를 이용하여 제작하고 그에 대한 특성평가와 적용 가능성에 대해 연구하였다. 버퍼-캐소드 하이브리드 투명 전극은 ZnO, Ag, ITO를 이용하였고, Ag와 ITO의 두께는 고정한 상태에서 버퍼 역할을 하는 ZnO의 두께를 변수(25 nm ~ 45 nm)로 하여 ZnO두께에 따른 광학적, 전기적, 구조적, 표면 특성을 분석하였다. ZnO/Ag/ITO 하이브리드 투명전극의 최적의 조건에서 92%의 높은 투과도와 7.6 Ohm/square의 낮은 면저항을 갖는 버퍼-캐소드 하이브리드 투명전극을 구현하였다. 제작한 ZnO/Ag/ITO 버퍼 하이브리드 투명전극을 인버티드 유기 태양전지에 적용한 결과 버퍼 ZnO층을 스핀 코팅으로 제작한 인버티트 유기 태양전지에 비해 현저하게 낮은 효율을 나타내는 것을 확인 하였다. 이러한 이유를 규명하기 위해 스핀 코팅한 ZnO박막과 스퍼터 한 ZnO박막의 구조적, 표면적 특성을 비교 분석 하였고, UPS 분석 결과 스핀 코팅한 ZnO 박막의 일함수(3.3 eV)에 비해 스퍼터 한 ZnO박막의 일함수(4.4 eV)가 더 큰 것을 확인 할 수 있었다. 이를 통해 인버티드 유기 태양전지 소자의 효율을 높이기 위해서는 광학적 전기적 특성뿐 아니라 적절한 일함수와 공정방법의 중요성을 확인 하였다.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.41-46
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• 2010

The interfacial adhesion strengths between screen-printed Ag film and epoxy resin-coated polyimide were evaluated by $180^{\circ}$ peel test method. Measured peel strength value was initially around $164.0{\pm}24.4J/m^2$, while the heat treatment during 24h at $120^{\circ}C$ increase peel strength up to $220.8{\pm}19.2J/m^2$. $85^{\circ}C/85%$ RH temperature/humidity treatment decrease peel strength to $84.1{\pm}50.8J/m^2$, which seems to be attributed to hydrolysis bonding reaction mechanism between metal and adhesive epoxy resin coating layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.92-96
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• 2002

A silver indium sulfide $(AgInS_{2})$ epilayer was grown by the hot wall epitaxy method, which has not been reported in the literature. The grown $AgInS_{2}$ epilayer has found to be a chalcopyrite structure and evaluated to be high quality crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks are ascribed to the band-ta-band transition. The valence band splitting of $AgInS_{2}$ was investigated by means of the photocurrent measurement. The crystal field splitting, $\Delta_{cr}$, and the spin orbit splitting, $\Delta_{so.}$ have been obtained to be 0.150 eV and 0.009 eV at 10 K, respectively. And, the energy band gap at room temperature has been determined to be 1.868 eV. Also, the temperature dependence of the energy band gap, $E_{g}(T)$, was determined.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.2
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• pp.63-69
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• 1996

D.c conductivity and optical transmittance of amorphous ($As_2Se_3$)Ag, (x =0, 2, 5, 10mol%) thin films were measured in order to find effects of Ag additives on electrical and optical properties of the films. The d.c. activation energy and the optical gap decreased with increasing Ag contents the Urbach tail was approximately unchangeable for variation of Ag contents. For Ag contents of 5mol% and less, the rate of decrease of the d.c activation energy was more rapidly than that of the optical gap with increasing Ag contents. For Ag contents more than 5mol%, the rate of decrease of the d.c activation energy and the optical gap were nearly the same each other with decreasing Ag contents. So it was appeared that the Fermi level of the films comes close to the mobility edge for Ag contents of 5mol% and less, and the mobility edge comes close the Fermi level for Ag contents more than 5mol%.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.311-321
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• 2007

We have researched the chemical defects of NiO ultrathin films grown on Ag(001) by x-ray photoelectron spectroscopy. In particular, O 1s and Ni 2p spectra were analyzed consistently with control film thickness, $O_2\;and\;H_2O$ partial pressure and substrate temperature. As a result, we could identify each chemical defect. In addition, we suggest the optimum growth condition to minimize the defect density.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2005.11a
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• pp.153-153
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• 2005

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.211-220
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• 1998

The stochiometric composition of $AgGaS_2$polycrystal source materials for the single crystal thin films were prepared from horizontal furnace. From the extrapolation method of X-ray diffraction patterns, it was found that the polycrystal $AgGaS_2$has tetragonal structure of which lattice constant $a_0\;and \;c_0$ were 5.756 $\AA$ and 10.305 $\AA$, respectively. $AgGaS_2$single crystal thin film was deposited on throughly etched GaAs(100) substrate from mixed crystal $AgGaS_2$by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $590^{\circ}C$ and $440^{\circ}C$ respectively, and the growth rate of the single crystal thin films was about 0.5 $mu \textrm{m}$/h. The crystallinity of the grown single crystal thin films was investigated by the DCRC (double crystal X-ray diffraction rocking curve). The optical energy gaps were found to be 2.61 eV for $AgGaS_2$single crystal thin films at room temperature. The temperature dependence of the photocurrent peak energy is well explained by the Varshni equation, then the constants in the Varshni equation are given by${\Alpha};=;8.695{\times}10^{-4};eV/K,and;{\beta};=;332;K$. from the photocurrent spectra by illumination of polarized light of the $AgGaS_2$single crystal thin film, we have found that crystal field splitting $\Delta$Cr was 0.28 eV at 20 K. From the PL spectra at 20 K, the peaks corresponding to free and bound excitons and a broad emission band due to D-A pairs are identified. The binding energy of the free excitons are determined to be 0.2676 eV and 0.2430 eV and the dissociation energy of the bound excitons to be 0.4695 eV.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.7-11
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• 2014

Recently, the buffer layers consisting of poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT-PSS) are extensively used to improve power conversion efficiency (PCE) of organic solar cells. However, PEDOT-PSS is not suitable for mass production of organic solar cells due to its intrinsic acid and hygroscopic properties. Moreover, because of chemical reactions between indium tin oxide (ITO) layer and PEDOT-PSS layer, the interface is not stable. For these reasons, alternative materials such as $V_2O_5$ have been developed to be an effective buffer layer. In this work, we used $V_2O_5$/Ag/ITO multilayer structure for the anode buffer layer. With variation of thickness of Ag layer, we investigated the optical and electrical properties of $V_2O_5$/Ag/ITO multi-layer films. As a result, we found that the electrical properties were improved with increasing Ag thickness while optical transmittance decreases in visible wavelength region. From the calculation of figure of merit (FOM) which is used to evaluate proper structure for transparent of optoelectronic, $V_2O_5$/Ag/ITO multilayer electrode was optimized with 4 nm thick Ag layer in optical (88% in transmittance) and electrical ($4{\times}10^{-4}{\Omega}cm$) properties. This indicates that $V_2O_5$/Ag/ITO multilayer electrode could be a candidate for the anode of optoelectronic devices.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.131-137
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• 1998

The thickness dependence of the microstructure and the giant magnetoresistance behavior of co-evaporated Co-Ag granular alloy films were investigated. The maximum magnetoresistance ratio of 24% was observed in the the as-deposited state of the 40 at. % Co alloy having 200 nm thickness. The surface scattering contributed about 20% to the total resistivity in the 20 nm thick films. The MR ratio dropped sharply when the film thickness was below 50 nm. The reduction in the Co particle size and the increase in solid solubility of Ag in fcc Co when the film thickness decreased were observed using a high resolution TEM. The aspect ratio of the Co particles was also affected by the film thickness. Those microstructural changes as well as the surface induced spin flipping play a significant role in the $\Delta$p change.

• Journal of the Korean Magnetics Society
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• v.11 no.2
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• pp.63-71
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• 2001

The effects of an Ag seed layer on the magnetic properties and the microstructural evolution of SmCo/Cr thin films deposited on glass substrates were investigated. Coercivity of the films is 2.0 kOe when the thickness of Ag seed layer was 1nm thick, but it increased to 2.7 kOe when the Ag seed layer thickness is 3 nm. The increase of coercivity for film with 3 nm-thick Ag is due to roughness of Cr and grain size of Cr by the Ag microbumps. Ar partial pressure influenced on the formation of Ag microbumps, for example, they were formed at 5 mTorr when Ag thickness was 1 nm. The mechanism of magnetization reversal of the SmCo films changed from domain wall motion to domain rotation as the Ag inserted. This was thought to be due to inhibition of domain wall motion by the reduction of Cr grain size and the increase of roughness.