• Journal of the Korean institute of surface engineering
• /
• v.43 no.3
• /
• pp.148-153
• /
• 2010

Transparent conducting films having a hybrid structure of GZO/Metal/GZO were prepared on glass substrates by sequential deposition using DC magnetron sputtering. Silver, copper, aluminum and zinc thin films were used as the intermediate metal layers in the hybrid structure. The electrical and optical properties of hybrid transparent conducting films were investigated with varying the thickness of metal layer or GZO layers. With increasing the metal thickness, hybrid films showed a noticeable improvement of the electrical conductivity, which is mainly dependent on the electrical property of the metal layer. GZO(40 nm)/Ag(10 nm)/GZO(40 nm) film exhibits a resistivity of $5.2{\times}10^{-5}{\Omega}{\cdot}cm$ with an optical transmittance of 82.8%. For the films with Zn interlayer, only marginal reduction in the resistivity was observed. Furthermore, unlike other metals, hybrid films with Zn interlayer showed a decrease in the resistivity with increasing the GZO thickness. The optimal thickness of GZO layer for anti-reflection effect at a given thickness of metal (10 nm) was found to be critically dependent on the refractive index of the metal. In addition, x-ray diffraction analysis showed that the insertion of Ag layer resulted in the improvement of crystallinity of GZO films, which is beneficial for the electrical and optical properties of hybrid-type transparent conducting films.

• Journal of the Korea Convergence Society
• /
• v.13 no.3
• /
• pp.197-202
• /
• 2022

The CZTS solar cell is a thin film solar cell using an absorption layer composed of Cu, Zn, Sn, Se, and S, and is cheaper than a CIGS solar cell using In and Ga and more eco-friendly than a perovskite and CdTe solar cell using Pb and Cd. In this study, we conducted a bending test for flexible CZTS solar cells. Experiments were conducted in the direction of inner benidng with compressive stress and outer bending with tensile stress, and during the number of bending 1,000 times with a radius of curvature of 50 mmR, the efficiency of the solar cell decreased by up to 12.7%, and the biggest cause of efficiency reduction in both directions was a large decrease in parallel resistance.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.62.1-62.1
• /
• 2010

CIS(CuInSe2)계 화합물 태양전지는 높은 광흡수계수와 열적 안정성 및 조성 조절을 통한 밴드갭 조절이 용이해 고효율 박막 태양전지로 각광 받고 있다. 또한 CIGS 태양전지는 기존의 유리기판 대신 유연한 기판을 사용해 flexible 태양전지 제조가 가능하다. 이러한 유연기판은 보통 stainless steel과 같은 금속 기판이 많이 사용되는데 기존의 soda-lime glass 기판과는 달리 금속기판에는 Na이 첨가되어 있지 않아 별도의 Na첨가를 필요로 한다. Na은 CIGS 흡수층의 조성조절을 용이하게 하여 태양전지의 변환 효율을 향상시키는 역할을 한다. 본 연구에서 기판은 Na이 첨가되어있지 않은 corning glass를 사용 하였으며 NaF를 이용해 Mo가 증착된 기판에 NaF의 두께를 달리하며 증착해 CIGS 흡수층의 grain 사이즈를 비교 하였으며 그 후 태양전지 소자를 제조해 광전특성을 분석하였다. 후면 전극으로 약60nm 두께의 Mo를 DC Sputtering 방법을 이용해 증착 하였다. buffer층으로는 약 50nm의 CdS층을 CBD방법을 이용하여 제조 하였으며 TCO 층으로 약 50nm의 i-ZnO와 약 450nm의 Al-ZnO를 RF Sputtering방법으로 증착 하였다. 마지막으로 앞면 전극으로 약 $1{\mu}m$의 Al을 Thermal Evaporation방법으로 증착하였다. 태양전지 소자의 면적은 $0.49cm^2$로 효율을 비교 분석하였다.

• Journal of electromagnetic engineering and science
• /
• v.8 no.3
• /
• pp.129-133
• /
• 2008

An integrated passive device(IPD) technology by semi-insulating(SI)-GaAs-based fabrication has been developed to meet the ever increasing needs of size and cost reduction in wireless applications. This technology includes reliable NiCr thin film resistor, thick plated Cu/Au metal process to reduce resistive loss, high breakdown voltage metal-insulator-metal(MIM) capacitor due to a thinner dielectric thickness, lowest parasitic effect by multi air-bridged metal layers, air-bridges for inductor underpass and capacitor pick-up, and low chip cost by only 6 process layers. This paper presents the Wilkinson power divider with excellent performance for digital cellular system(DCS). The insertion loss of this power divider is - 0.43 dB and the port isolation greater than - 22 dB over the entire band. Return loss in input and output ports are - 23.4 dB and - 25.4 dB, respectively. The Wilkinson power divider based on SI-GaAs substrates is designed within die size of $1.42\;mm^2$.

• Progress in Superconductivity
• /
• v.6 no.1
• /
• pp.19-23
• /
• 2004

YBCO do superconducting quantum interference device (SQUID) magnetometers based on bicrystal Josephson junctions on 10 mm ${\times}$ 10 mm $SrTiO_3$ substrates have been fabricated. The pickup coil of the device was designed to have 16 parallel loops with 50-fm-wide lines. We could obtain optimised direct coupled YBCO SQUID magnetometer design with field sensitivity $B_{N}$ $\Phi$/ of $4.5 nT/\Phi_{0}$ and magnetic field noise $B_{N}$ of about $22 fT/Hz^{1}$2/ with an I/f corner frequency of 2 Hz measured inside a magnetically shielded room. Preliminary results of magnetocardiograph measurement using the HTS SQUID magnetometers show signal to noise ratio of about 110, which is comparable to the quality of a commercial MCG system based on Nb-SQUIDs.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.877-881
• /
• 2006

We obtained sputtering yields for the MgO, $MgAl_2O_4$ and $MgAl_2O_4/MgO$ films using the FIB system. $MgAl_2O_4/MgO$ protective layers have been found to have less $24^{\sim}^30%$ sputtering yield values from 0.24 atoms/ion up to 0.36 atoms/ion than MgO layers with the values from 0.36 atoms/ion up to 0.45 atoms/ion for irradiated $Ga^+$ ion beam whose energies ranged from 10 keV to 14 keV. And $MgAl_2O_4$ layers have been found to have lowest sputtering yield values from 0.88 up to 0.11. It is also found that $MgAl_2O_4/MgO$ and MgO have secondary electron emission $coefficient({\gamma})$ values from 0.09 up to 0.12 for $Ne^+$ ion whose energies ranged from 50 eV to 200 eV.

• 한국초전도학회:학술대회논문집
• /
• v.10
• /
• pp.193-196
• /
• 2000

A new type low-pass filter design method based on a coupled line and transmission line theory is proposed to suppress harmonics by attenuation poles in the stop band. The design formula are derived using the equivalent circuit of a coupled transmission line. The new low-pass filter structure is shown to have attractive properties such as compact size, wide stop band range and low insertion loss. The seventh-order low-pass filter designed by present method has a cutoff frequency of 0.9 CHz with a 0.01 dB ripple level. The coupled line type low-pass filter with strip line configuration was fabricated by using a high-temperature superconducting (HTS : YBa$_2$Cu$_3$O$_{7-{\delta}}$ thin film on MgO(100) substrate. Since the HTS coupled tine type low-pass filter was proposed with five attenuation poles in stop band such as 1.8, 2.5, 4, 5.5, 6.2 GHz. The fabricated low-pass filter has improved the attenuation characteristics up to seven times of the cutoff frequency.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.357.2-357.2
• /
• 2014

Ruthenium (Ru) 박막은 우수한 화학적 열적 안정성 및 높은 일함수(4.7eV) 특성으로 인해 20 nm급 이하의 차세대 DRAM capacitor의 전극 물질 및 Cu metalization을 위한 seed layer로 각광을 받고 있다. Ru박막의 나노스케일 정보전자소자로의 적용을 위해서는 두께제어가 용이하고 3D 구조에서 우수한 단차 피복 특성을 갖는 atomic layer deposition (ALD)을 이용한 박막 형성이 필수적이다. 이에 본 연구에서는 ALD 방법을 이용하여 0가의(cymene) (1,5-hexadiene) Ru (0) (C16H24Ru) 전구체를 합성, ALD 방법을 이용하여 우수한 초기성장거동을 갖는 Ru 박막을 증착 하였다. 형성된 Ru 박막의 표면 형상, 두께, 밀도를 주사전자현미경(Scanning electron microscopy)과 X-선 반사율 측정(X-ray reflectometer)으로 조사하였다. 또한 전기적 특성을 4침법(four-point-probe)으로 측정하였고, 박막의 화학적 조성과 결정성의 정보를 X-선 광전자분광법(X-ray photoelectron spectroscopy)과 X-선 회절(X-ray diffraction)을 이용하여 확인하였다.

• Proceedings of the KIEE Conference
• /
• 1999.11d
• /
• pp.873-875
• /
• 1999

We have fabricated good quality superconducting $YBa_{2}Cu_{3}O_{7-\delta}$ thin films on Hastelloy(Ni-Cr-Mo alloys) metallic substrate with $CeO_2$ and $BaTiO_3$ buffer layers in-situ by pulsed laser deposition in a multi-target processing chamber. We have chosen $CeO_2$ as a buffer layer which has cubic structure of $5.41{\AA}$ lattice parameter and only 0.2% of lattice mismatch with YBCO. $CeO_2$ layer may be helpful for power transmission due to its conducting property. In order to enhance the crystallization of YBCO films on metallic substrates. we deposited $CeO_2$ and $BaTiO_3$ buffer layers at various temperatures. The YBCO superconducting tape fabricated with $BaTiO_3$ and $CeO_2$ buffer layers shows 85K of transition temperature and about $8.4{\times}10^4A/cm^2$ of critical current density at 77K.

• Journal of the Korean Vacuum Society
• /
• v.4 no.3
• /
• pp.306-312
• /
• 1995

본 연구에서는 비정질 실리콘과 CuInSe2와 함께 지상용 태양전지재료로 널리 연구되고 있는 다결정 CdTe 박막의 열처리방법으로서 로열처리와 반도체 공정에서 사용되는 급속열처리 방법을 이용하여 이들 열처리의 효과를 분석함으로써 태양전지용 다결정 CdTeq 박막에 적합한 효율적인 열처리 방법에 대한 연구를 수행하였다. 증착 후 열처리조건에 따른 결정구조, 결정립 크기, 표면과 박막내부의 성분, 밴드갭 에너지값, 그리고 전기비저항 등을 측정하여 태양전지용 CdTe 박막의 물리적.전기적 특성에 미치는 열처리효과를 관찰하였다. 연구결과 30$0^{\circ}C$에서 증착하고 CdCI2 처리 후 $400^{\circ}C$ 30분간 로열처리를 한 경우, 그리고 $200^{\circ}C$에서 증착한 후 $500^{\circ}C$ 부근에서 1분간 급속열처리를 한 경우 다결정 CdTe 박막의 물리적 전기적 특성이 현저히 향상됨을 알 수 있었다. 특히 급속열처리를 한 경우 로열처리에 비해 결정립의 크기는 작으나 전기비저항이 낮고 밴드갭에너지가 단결정에 더욱 접근하며 태양전지용 다결정 CdTe 박막의 열처리 방법으로 적용할 가치가 있는 방법으로 사료된다.