• Title/Summary/Keyword: Zn electrode

Search Result 397, Processing Time 0.022 seconds

The Fabrication of Micro-electrodes to Analyze the Single-grainboundary of ZnO Varistors and the Analysis of Electrical Properties (ZnO 바리스터의 단입계면 분석을 위한 마이크로 전극 제작과 전기적 특성 해석)

  • So, Soon-Jin;Lim, Keun-Young;Park, Choon-Bae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.18 no.3
    • /
    • pp.231-236
    • /
    • 2005
  • To investigate the electrical properties at the single grainboundary of ZnO varistors, micro-electrodes were fabricated on the surface which was polished and thermally etched. Our micro-electrode had 2000 $\AA$ silicon nitride layer between micro-electrode and ZnO surface. This layer was deposited by PECVD and etched by RIE after photoresistor pattering process using by mask 1. The metal patterning of micro-electrodes used lift-off method. We found that the breakdown voltage of single grainboundary is about 3.5∼4.2 V at 0.1 mA on I-V curves. Also, capacitance-voltage measurement at single grainboundary gave several parameters( $N_{d}$, $N_{t}$, $\Phi$$_{b}$, t) which were related with grainboundary.ary.

N-Doped ZnO Nanoparticle-Carbon Nanofiber Composites for Use as Low-Cost Counter Electrode in Dye-Sensitized Solar Cells (염료감응형 태양전지의 저비용 상대전극을 위한 N-doped ZnO 나노입자-탄소나노섬유 복합체)

  • An, Ha-Rim;Ahn, Hyo-Jin
    • Korean Journal of Materials Research
    • /
    • v.24 no.10
    • /
    • pp.565-571
    • /
    • 2014
  • Nitrogen-doped ZnO nanoparticle-carbon nanofiber composites were prepared using electrospinning. As the relative amounts of N-doped ZnO nanoparticles in the composites were controlled to levels of 3.4, 9.6, and 13.8 wt%, the morphological, structural, and chemical properties of the composites were characterized by means of field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In particular, the carbon nanofiber composites containing 13.8 wt% N-doped ZnO nanoparticles exhibited superior catalytic properties, making them suitable for use as counter electrodes in dye-sensitized solar cells (DSSCs). This result can be attributed to the enhanced surface roughness of the composites, which offers sites for $I_3{^-}$ ion reductions and the formation of Zn3N2 phases that facilitate electron transfer. Therefore, DSSCs fabricated with 13.8 wt% N-doped ZnO nanoparticle-carbon nanofiber composites showed high current density ($16.3mA/cm^2$), high fill factor (57.8%), and excellent power-conversion efficiency (6.69%); at the same time, these DSSCs displayed power-conversion efficiency almost identical to that of DSSCs fabricated with a pure Pt counter electrode (6.57%).

Effect of Oxygen Pressure on the Electrical Properties of ZnO Transparent Thin Films on Flexible Teflon Substrate (산소압력이 테프론 휨성 기판위에 형성된 ZRO 투명박막의 전기적 특성에 미치는 영향)

  • Suh Kwang Jong;Chang Ho Jung
    • Korean Journal of Materials Research
    • /
    • v.15 no.4
    • /
    • pp.271-274
    • /
    • 2005
  • We investigated the crystalline and electrical properties of ZnO thin films for transparent electrode as a function of the oxygen pressures during the deposition. The ZnO thin films were deposited on a flexible teflon substrates by the pulsed laser deposition. From the X-ray diffraction, ZnO films showed c axis oriented ZnO(0002) crystal structure. The FWHM (full width at half maximum) values decreased from $0.51^{\circ}\;to\;0.34^{\circ}$ as the oxygen pressure increased from 0.1 mTorr to 10.0 mTorr showing the improvement of crystallinity. The resistivity and hall mobility of ZnO film deposited at the oxgen pressure of 0.1 mTorr at $200^{\circ}C$ was about $5\times10^{-4}\Omega{\cdot}cm\;and\;20cm^2/V{\cdot}s$, respectively. The optical transmittance of the ZnO films on flexible teflon substrate was found to be above $85\%$.

A Study on the ZnO Piezoelectric Thin Film SAW Filter for High Frequency (ZnO 압전 박막을 이용한 고주파 SAW 필터 연구)

  • 박용욱;신현용
    • Journal of the Korean Ceramic Society
    • /
    • v.40 no.6
    • /
    • pp.547-552
    • /
    • 2003
  • ZnO thin films on glass substrate were deposited by RF magnetron reactive sputtering at 100 W, 1.33 Pa, Ar/O2=50 : 50, 200$^{\circ}C$, and a target/substrate distance of 4 cm. Crystallinities, surface morphologies, chemical compositions, and electrical properties of the films were investigated by XRD, SEM, AFM, RBS, and electrometer. All films showed a strong preferred c-axis orientation and the chemical stoichiometry. The propagation velocity of ZnO/IDT/glass of single electrode and double electrode types SAW filter was about 2,589 m/sec, 2,533 m/sec and insertion loss was a minimum value of about -11 dB and -21 dB, respectively.

Redox Properties of Modified Poly-N,N'-bis(2-pyrrol-1-yl-propyl)-4,4'-Bipyridine Film Electrode (수식된 N,N'-bis(2-pyrrol-1-yl-propyl)-4,4'-bipyridine 고분자 피막전극의 산화-환원 특성)

  • Cha, Seong Keuck
    • Journal of the Korean Chemical Society
    • /
    • v.45 no.5
    • /
    • pp.429-435
    • /
    • 2001
  • The monomer N,N'-bis(2-pyrrol-1-yl-propyl)-4,4'-bipyridine(bpb) was electrochemically polymerized on the glassy carbon electrode surface, which was modified with 1:1 ratio of erichrome black T(EBT) and glutathione(GSSG) to give a type of GC/poly-bpb, EBT, GSSG electrode for depositing Zn(II). The diffusion coefficients of the incorporated ions were 2.43${\times}10^{-15}$ and 9.14${\times}10^{-15} cm^2s^{-1}$ before taking Zn(II) ions and after them respectively. The modified electrodes are stable at the electrode process. The polymerized poly-bpb of 2.83${\times}10^4gmol^{-1}$ can deposit 2.15${\times}10^4gmol^{-1}$ of Zn(II). The number of pumping ions involving in the redox procedure at 0.77 V was 81.7% of the captured 180 ions into the polymer matrix, which was 3 times larger than that of the electrode modified with EBT alone.

  • PDF

Electrodeposition of Graphene-Zn/Al Layered Double Hydroxide (LDH) Composite for Selective Determination of Hydroquinone

  • Kwon, Yeonji;Hong, Hun-Gi
    • Bulletin of the Korean Chemical Society
    • /
    • v.34 no.6
    • /
    • pp.1755-1762
    • /
    • 2013
  • A graphene-Zn/Al layered double hydroxide composite film was simultaneously prepared by electrochemical deposition on the surface of a glassy carbon electrode (G-LDH/GCE) from the mixture solution containing GO and nitrate salts of $Zn^{2+}$ and $Al^{3+}$. The modified electrode showed good electrochemical performances toward the simultaneous electrochemical detection of hydroquinone (HQ), catechol (CA) and resorcinol (RE) due to the unique properties of graphene (G) and LDH such as large active surface area, facile electronic transport and high electrocatalytic activity. The redox characteristics of G-LDH/GCE were investigated with cyclic voltammetry and differential pulse voltammetry. The well-separated oxidation peak potentials, corresponding to the oxidation of HQ, CA and RE, were observed at 0.126 V, 0.228 V and 0.620 V respectively. The amperometric response of the modified electrode exhibited that HQ can be detected without interference of CA and RE. Under the optimized conditions, the oxidation peak current of HQ is linear with the concentration of HQ from 6.0 ${\mu}M$ to 325.0 ${\mu}M$ with the detection limit of 0.077 ${\mu}M$ (S/N=3). The modified electrode was successfully applied to the direct determination of HQ in a local tap water, showing reliable recovery data.

Characteristics of Wire EDM for Cold Die Steel due to the Different Wire Electrode Component (전극선 성분 변화에 따른 냉간금형용강의 와이어방전가공 특성)

  • Wang, Duck-Hyun;Jeong, Sun-Sung
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.2 no.2
    • /
    • pp.98-105
    • /
    • 2003
  • In the experimental study, wire EDM was conducted for cold die steel by changing the Wire electrode, peak discharge current and number of finish cut. From the micro structure analysis of SEM photographs, the size of irregular welded and added component on the EDMed surface is decreasing and size of EDMed plane surface is increasing as the decreasing peak current and increasing number of finish cut. From the analysis of coating effect, Zn component is highly contained in Br and Zn Wire EDMed surface and copper component is highly contained in Br and Al wire EDMed surface. Hardness values are Increasing as the increasing peak current and decreasing the number of finish cut The value of hardness is decreasing as Cu, Al, Zn and Br wire electrode because of the residual austenite effect of solid solution copper on solidification, and finally EDMed surface has the highest hardness values for every wire electrode. Yield strength values becomes larger and bending strength values become smaller due to the increasing the hardness. These results are increased as increasing brittleness with hardness.

  • PDF

Solution-Processed Anti Reflective Transparent Conducting Electrode for Cu(In,Ga)Se2 Thin Film Solar Cells (CIGS 박막태양전지를 위한 반사방지특성을 가진 용액공정 투명전극)

  • Park, Sewoong;Park, Taejun;Lee, Sangyeob;Chung, Choong-Heui
    • Korean Journal of Materials Research
    • /
    • v.30 no.3
    • /
    • pp.131-135
    • /
    • 2020
  • Silver nanowire (AgNW) networks have been adopted as a front electrode in Cu(In,Ga)Se2 (CIGS) thin film solar cells due to their low cost and compatibility with the solution process. When an AgNW network is applied to a CIGS thin film solar cell, reflection loss can increase because the CdS layer, with a relatively high refractive index (n ~ 2.5 at 550 nm), is exposed to air. To resolve the issue, we apply solution-processed ZnO nanorods to the AgNW network as an anti-reflective coating. To obtain high performance of the optical and electrical properties of the ZnO nanorod and AgNW network composite, we optimize the process parameters - the spin coating of AgNWs and the concentration of zinc nitrate and hexamethylene tetramine (HMT - to fabricate ZnO nanorods. We verify that 10 mM of zinc nitrate and HMT show the lowest reflectance and 10% cell efficiency increase when applied to CIGS thin film solar cells.

Comparison of Luminescence Properties of Electrochemical Luminescence Cells for Various Electrode Materials and Structures

  • Pooyodying, Pattarapon;Ok, Jung-Woo;Sung, Youl-Moon
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.4
    • /
    • pp.1605-1610
    • /
    • 2017
  • The electrochemical luminescence (ECL) device was investigated, which has similar structure to the dye-sensitized solar cell. The structure of the ECL cell in this experiment reliably induces a large amount of the oxidation around electrodes. The band gap of the ECL electrode is of 3.0 - 3.2 eV. Titanium dioxide ($TiO_2$) nanoparticle has following properties: a band gap of 3.4 eV, a low-priced material, and 002 preferred orientation (Z-axis). Zinc Oxide (ZnO) nanorod is easy to grow in a vertical direction. In this paper, in order to determine material suitable for the ECL device, the properties of various materials for electrodes of ECL devices such as ZnO nanorod (ZnO-NR) and $TiO_2$ nanoparticle ($TiO_2-NP$) were compared. The threshold voltage of the light emission of the ZnO-NR was 2.0 V which is lower than 2.5 V of $TiO_2-NP$. In the other hand, the luminance of $TiO_2-NP$ was $44.66cd/m^2$ and was higher than that of $34cd/m^2$ of ZnO-NR at the same applied voltage of 4 V. Based on the experimental results, we could conclude that $TiO_2-NP$ is a more suitable electrode material in ECL device than the ZnO-NR.

Study of ITO/ZnO/Ag/ZnO/ITO Multilayer Films for the Application of a very Low Resistance Transparent Electrode on Polymer Substrate

  • Han, Jin-Woo;Han, Jeong-Min;Kim, Byoung-Yong;Kim, Young-Hwan;Kim, Jong-Yeon;Ok, Chul-Ho;Seo, Dae-Shik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.20 no.9
    • /
    • pp.798-801
    • /
    • 2007
  • Multilayer transparent electrodes, having a much lower electrical resistance than the widely used transparent conducting oxide electrodes, were prepared by using radio frequency magnetron sputtering. The multilayer structure consisted of five layers, indium tin oxided (ITO)/zinc oxide (ZnO)/Ag/zinc oxide (ZnO)/ITO. With about 50 nm thick ITO films, the multilayer showed a high optical transmittance in the visible range of the spectrum and had color neutrality. The electrical and optical properties of ITO/ZnO/Ag/ZnO/ITO multilayer were changed mainly by Ag film properties, which were affected by the deposition process of the upper layer. Especially ZnO layer was improved to adhesion of Ag and ITO. A high quality transparent electrode, having a resistance as low as and a high optical transmittance of 91% at 550 nm, was obtained. It could satisfy the requirement for the flexible OLED and LCD.