• Title, Summary, Keyword: electronic structure

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Processing Study for the Piezoelectric Energy Harvest of Composit Structure (복합구조의 압전 에너지 하베스터를 위한 공정연구)

  • Lee, Kyoung-Soo;Shin, Dong-Jin;Koh, Jung-Hyuk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.4
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    • pp.286-289
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    • 2012
  • In this paper, we have proposed piezoelectric energy harvester employing the pillar structure with the diameter size of 500 um. So we have selected the Su-8 photo-resist and modified lithography process to manufacture the pillar structure with height above the $500{\mu}m$. Simultaneously, we tried to make a comparative study to use ceramic bulk - polymer structure In this paper, we will report the process and properties of micro pillar structure based on the PMN-PZT ($Pb(Mg_{1/3}Nb_{2/3})O_3-PbZrTiO_3$) materials. Finally, We will propose a method for generating electrical energy with a piezoelectric element using vibration, an energy source can be obtained from the "clean" energy.

The Evolution of Market Mechanism in B2B Electronic Commerce: An Exploratory Study (기업간 전자상거래시장의 시장 메커니즘 진화에 관한 탐색적 연구 -Electronic Market 가설을 중심으로-)

  • 김효근;홍진영;정성휘
    • The Journal of Society for e-Business Studies
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    • v.6 no.3
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    • pp.41-61
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    • 2001
  • Many markets are forecast to see significant changes due to the growth of electronic commerce made possible by the internet. The way of doing business with internet affects the market mechanism. It is now over 10 years since Malone et al(1987) set out their hypothesis on electronic markets, and electronic hierarchies. An electronic market is an interorganizational information system through which multiple buyers and sellers interact to accomplish one or more of the following market-making activities. And they predicted that markets evolve toward electronic markets, by reducing search cost, which may result in significantly. higher price competition among sellers and therefore lower prices for buyers. And the degree of two factors; asset specificity and uncertainty, affect the market mechanism. Products with low asset specificity and low uncertainty are compatible with a market relationship while the greater the asset specificity and uncertainty, the more likely it is to favour a hierarchical structure. Based on the these researches, we observed and analyzed a case study of market mechanism in Internet business. We found the fact that even though Internet could make the business environment in which lots of buyers and suppliers participate, electronic market will evolve market mechanism. 1 analyzed two factors, which affected market evolution. First, When Asset specificity is low in electronic commerce, market structure should be preferred to hierarchical structure. Second, When transaction uncertainty is low in electronic commerce, market structure should be preferred In hierarchical structure. This research covers conceptual and empirical aspects on electronic market structure. Future research should be variously done about the influential factors of electronic market mechanism.

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Low on Resistance Characteristic with 2500V IGBTs (낮은 온-저항 특성을 갖는 2500V급 IGBTs)

  • Shin, Samuell;Son, Jung-Man;Ha, Ka-San;Won, Jong-Il;Jung, Jun-Mo;Koo, Yong-Seo
    • Proceedings of the IEEK Conference
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    • pp.563-564
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    • 2008
  • This paper presents a new Insulated Gate Bipolar Transistor(IGBT) for power switching device based on Non Punch Through(NPT) IGBT structure. The proposed structure has adding N+ beside the P-base region of the conventional IGBT structure. The proposed device has faster turn-off time and lower forward conduction loss than the conventional IGBT structure.

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Electrical characteristic of Phase-change Random Access Memory with improved bottom electrode structure (하부전극 구조 개선에 의한 상변화 메모리의 전기적 특성)

  • Kim, Hyun-Koo;Choi, Hyuk;Cho, Won-Ju;Chung, Hong-Bay
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.69-70
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    • 2006
  • A detailed Investigation of cell structure and electrical characteristic in chalcogenide-based phase-change random access memory(PRAM) devices is presented. We used compound of Ge-Sb-Te material for phase-change cell. A novel bottom electrode structure and manufacture are described. We used heat radiator structure for improved reset characteristic. A resistance change measurement is performed on the test chip. From the resistance change, we could observe faster reset characteristic.

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Fabrication of phosphorus doped ZnO thin film using multi-layer structure (다층 구조를 이용한 Phosphorus 도핑된 ZnO 박막 제작)

  • Kang, Hong-Seong;Lim, Sung-Hoon;Chang, Hyun-Woo;Kim, Gun-Hee;Kim, Jong-Hoon;Lee, Sang-Yeol
    • Proceedings of the KIEE Conference
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    • pp.27-29
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    • 2005
  • ZnO and phosphorus doped ZnO thin films (ZnO:P) are deposited by pulsed laser deposition grown on (001) $Al_{2}O_{3}$. ZnO/ZnO:P/ZnO/$Al_{2}O_{3}$ (multi-layer) structure was used for phosphorus doped ZnO fabrication. This multi-layer structure thin film was annealed at $400^{\circ}C$ for 40 min. The electron concentration of that was changed from $10^{19}$ to $10^{16}/cm^{-3}$ after annealing. ZnO thin films with encapsulated structure showed the enhanced structural and optical properties than phosphorus doped ZnO without encapsulated layer. In this study, encapsulated ZnO structure was suggested to enhance electrical, structural and optical properties of phosphorus doped ZnO thin film and it was identified that encapsulated structure could be used to fabricate high quality phosphorus doped ZnO thin film.

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Electronic Structure of Ce-doped ZrO2 Film: Study of DFT Calculation and Photoelectron Spectroscopy

  • Jeong, Kwang Sik;Song, Jinho;Lim, Donghyuck;Kim, Hyungsub;Cho, Mann-Ho
    • Applied Science and Convergence Technology
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    • v.25 no.1
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    • pp.19-24
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    • 2016
  • In this study, we evaluated the change of electronic structure during redox process in cerium-doped $ZrO_2$ grown by sol gel method. By sol-gel method, we could obtain cerium-doped $ZrO_2$ in high oxygen partial pressure and low temperature. After post annealing process in nitrogen ambient, the film is deoxidized. We used spectroscopic and theoretical methods to analysis change of electronic structure. X-ray absorption spectroscopy (XAS) for O K1-edge and Density Functional Theory (DFT) calculation using VASP code were performed to verify the electronic structure of the film. Also, high resolution x-ray photoelectron spectroscopy (HRXPS) for Ce 3d was carried out to confirm chemical bond of cerium doped $ZrO_2$. Through the investigation of the electronic structure, we verified as followings. (1) During reduction process, binding energy of oxygen is increase. Simultaneously, oxidation state of cerium was change to 4+ to 3+. (2) Cerium 4+ and cerium 3+ states were generated at different energy level. (3) Absorption states in O K edge were mainly originated by Ce 4+ $f_0$ and Ce 3+, while occupied states in valance band were mainly originated from Ce 4+ $f_2$.

The Thermal and Optical Properties of Te-based Antireflection structure for Optical Recording (광기록을 위한 Te-based Antireflection구조의 열적, 광학적 특성)

  • Lee, S.J.;Lee, H.Y.;Chung, H.J.;Lee, Y.J.
    • Proceedings of the KIEE Conference
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    • pp.1256-1258
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    • 1993
  • Optical data storage offer high density storage and archival storage capability. In this study, we selected the ablation mechanism-one of an irreversible recording system-using the antireflection trilayer(ART) structure. Optical recording medium is a $(Te_{86}Se_{14})_{50}Bi_{50}$ thin films. Actually, ART structure is fabricated and compared to monolayer structure. ART structure leads to the reduction of recording power as well as an increase in the effciency compared to the monolayer structure.

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Lattice Deformation and Electronic Structure of the $C_{60}{^+}$ Cation

  • 이기학;이한명;전희자;박성수;이왕로;Park, T. Y.;Xin Sun
    • Bulletin of the Korean Chemical Society
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    • v.17 no.5
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    • pp.452-457
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    • 1996
  • The effects caused by the ionization on the electronic structure and geometry on C60 are studied by the modified Su-Schriffer-Heeger (SSH) model Hamiltonian. After the ionization of C60, the bond structure of the singly charged C60 cation is deformed from Ih symmetry of the neutral C60 to D5d, C1, and C2, which is dependent upon the change of the electron-phonon coupling strength. The electronic structure of the C60+ cation ground state undergoes Jahn-Teller distortion in the weak electron-phonon coupling region, while self-localized states occur in the intermediate electron-phonon region, but delocalized electronic states appear again in the strong electron-phonon region. In the realistic strength of the electron-phonon coupling in C60, the bond structure of C60+ shows the layer structure of the bond distortion and a polaron-like state is formed.

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Electrical Properties of Organic Materials as Low Dielectric Constant Materials

  • Oh Teresa;Kim Hong Bae;Kwon Hak Yong;Son Jae Gu
    • Journal of the Semiconductor & Display Technology
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    • v.4 no.3
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    • pp.5-9
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    • 2005
  • The bonding structure of organic materials such as fluorinated amorphous carbon films was classified into two types due to the chemical shifts. The electrical properties of fluorinated amorphous carbon films also showed very different effect of two types notwithstanding a very little difference. Fluorinated amorphous carbon films with the cross-link break-age structure existed large leakage current resulting from effect of the electron tunneling. Increasing the cation due to the electron-deficient group increased the barrier height of the films with the cross-link amorphous structure, therefore the electric characteristic of the final materials with low dielectric constant was also improved. The lowest dielectric constant is 2.3 at the sample with the cross-link amorphous structure.

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Band Electronic Structure Study of Compound $(ET)_2ICl_2$ in Two Structural Modifications

  • Kang Dae Bok
    • Bulletin of the Korean Chemical Society
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    • v.15 no.6
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    • pp.428-432
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    • 1994
  • The crystals of ${\beta}-and\;{\beta}'-(ET)_2ICl_2$ have a modified structure of organic superconductor ${\beta}(ET)_2I_3$. These salts possess strictly different physical properties : the ${\beta}$ phase is a metal but the ${\beta}'$ phase is a semiconductor. Our band electronic structure calculations show that the ${\beta}$ phase is somewhat anisotropic 2D metal and the ${\beta}'$ phase with the 1D character in electronic structure is magnetic insulating, in good agreement with experimental indications.

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