• Title/Summary/Keyword: carrier transport

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Numerical analysis of HgCdTe heterojunction photodiodes (HgCdTe 이종접합 광다이오드의 수치 해석)

  • 조남홍;곽규달
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.7
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    • pp.45-55
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    • 1997
  • Electircal characteristics of HgCdTe photodiodes with a heterostructure to achieve high performance are analyzed numerically. A two-dimensional device simulator which can handle a HgCdTe heterostructure, was developed for this work. The effects of band nonparabolicity, carrier degeneracy, and band-offset of heterointerace are included in a carrier transport model. A unified generation-recombination model includes simultaneously phonon-assisted tunneling and pure tunneling of carriers via traps is newly employed for describing the electric field and temperature dependency of dark current effectively. Furthermore, to accurately predict the effect mole fraction variations on genration rates, ray-trace algorithm is incorporated in the our simulator. Under the various circumstances such as dark, illumination, and surface states, electrical properties of planar heterostructure photodiode are presented and those of homojunction are compared. These results serve as a explanation of cap layer's role on performance.

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Investigation of Carrier Transport Mechanism in Schottky Type InAs/GaAs Quantum Dot Solar Cells

  • Kim, Ho-Seong;Ryu, Geun-Hwan;Yang, Hyeon-Deok;Park, Min-Su;Kim, Sang-Hyeok;Song, Jin-Dong;Choe, Won-Jun;Park, Jeong-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.319.1-319.1
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    • 2014
  • We present the results on the indium tin oxide (ITO) Schottky barrier solar cells (SBSCs) with InAs quantum dots (QDs). The dependence of external quantum efficiency on the external bias voltage has been studied to anlayze carrier extraction through tunneling at room temperature.

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The moving photocarrier grating technique for the determination of transport parameters in a-Se:As films

  • Park, Chang-Hee;Lee, Kwang-Sei;Kim, Jae-Hyung;Nam, Sang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.47-48
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    • 2005
  • The moving photocarrier grating(MPG) technique for the determination of the carrier mobilities and the recombination lifetime in a-Se:As films have been studied. The electron and hole drift mobility and the recombination lifetime of a-Se films with arsenic (As) additions have been obtained. We have found an increase in hole drift mobility and recombination lifetime, especially when 0.3% As is added into a-Se film. However, the electron mobility exhibits no observable change up to 0.5% As addition in a-Se films.0.3% As added a-Se film also exhibits the maximum short circuit current densities per laser intensity of $5.29\times10^{-7}$ A/W.

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Gate-tunable Supercurrent in Graphene-based Josephson Junction (그래핀 조셉슨 접합에서 초전류의 게이트 전압 의존성)

  • Jeong, D.;Lee, G.H.;Doh, Y.J.;Lee, H.J.
    • Progress in Superconductivity
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    • v.13 no.1
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    • pp.47-51
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    • 2011
  • Mono-atomic-layer graphene is an interesting system for studying the relativistic carrier transport arising from a linear energy-momentum dispersion relation. An easy control of the carrier density in graphene by applying an external gate field makes the system even more useful. In this study, we measured the Josephson current in a device consisting of mono-layer graphene sheet sandwiched between two closely spaced (~300 nm) aluminum superconducting electrodes. Gate dependence of the supercurrent in graphene Josephson junction follows the gate dependence of the normal-state conductance. The gate-tunable and relatively large supercurrent in a graphene Josephson junction would facilitate our understanding on the weak-link behavior in a superconducting-normal metal-superconducting (SNS) type Josephson junction.

The Moving Photocarrier Grating (MPG) Technique for the Transport Properties of α-Se:As Films

  • Park, Chang-Hee;Lee, Kwang-Sei;Kim, Jeong-Bae;Kim, Jae-Hyung
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.6
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    • pp.280-283
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    • 2005
  • The moving photocarrier grating (MPG) technique for the determination of the carrier mobilities and the recombination lifetime of $\alpha$-Se:As films has been studied. The electron and hole drift mobility and the recombination lifetime of $\alpha$-Se films with arsenic (As) additions have been obtained from measurement of the short circuit current density $j_{sc}$ as a function of grating velocity and spatial period. The hole mobility decreases due to defect density of hole traps when x exceeds 0.003, whereas the hole mobility increases for the case of low As addition (x$\le$0.003). We have found an increase in hole drift mobility and recombination lifetime, especially when As with (x = 0.003) is added into the $\alpha$-Se film.

Apoplastic Phloem Loading of Photoassimilate (광합성산물의 아포플라스트 체관부적재 기작)

  • Kim, Song-Mun;Hur, Jang-Hyun;Han, Dae-Sung
    • Korean Journal of Weed Science
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    • v.17 no.4
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    • pp.345-361
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    • 1997
  • Photoassimilates translocate from regions of carbohydrate synthensis(source) to regions of carbohydrate utilization or storage(sink). In the source, assimilate loads into the phloem for long-distance transport. Current evidence suggests that there are twig loading mechanisms : one involves assimilate transfer via the apoplasm and then load into the phloem by carrier-mediated proton-sucrose cotransport, while the other involves movement through the continuous symplastic connections between the mesophyll cells and the phloem. Inspite of problems associated with the interpretation of experiments, the evidence for apoplastic loading remains convincing because the apoplastic loading systems explains well the observed accumulation capacity arid the selectivity of assimilate uptake by tile phloem.

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<100>, <110>, <111>방향 Si, InAs Nanowire nMOSFETs 의 성능 연구

  • Jeong, Seong-U;Park, Sang-Cheon
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.357-361
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    • 2016
  • Si와 InAs 두 가지 채널 물질을 가지고 3가지 수송 방향 <100>, <110>, <111>으로 변화시키며 각각의 Nanowire nMOSFETs을 가지고 ballistic quantum transport simulation을 진행하였다. 각각의 경우에 대해 E-k curve를 구한 다음에 band curvature로 캐리어의 유효질량을 계산하고, 이를 통해 MOSFET의 전류 세기를 결정짓는 DOS와 carrier injection velocity를 구하여 어떤 경우에 가장 높은 ON-current를 흐르게 하는지 확인해 보았다. 하지만 예상과 달리 나노와이어의 직경이 1.4nm으로 매우 작기 때문에 valley-splitting이 일어나 Si<110>의 경우에 가장 작은 캐리어 유효 질량을 갖고 있는 사실을 확인할 수 있었다. 결론적으로 Si<100>의 경우에 trade-off 관계에 있는 DOS와 carrier injection velocity가 6가지 경우 중 최적의 조합을 가짐으로써 가장 높은 ON-current를 흐르게 하였다.

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A Study of the High Sensitive Nonsilver Halide Imaging Material( II ) - Study of the aqueous coating mechanism and washing effect of the CGL in the $\varepsilon$-CuPc/PVK double-layered organic photoconductor - (고감도 비은염 화상재료 개발연구 ( II ) - Copper Phthalocyanine/PVK 전자사진감광체의 CGL의 수성 coating mechanism과 세정효과에 관한 연구 -)

  • 이상남
    • Journal of the Korean Graphic Arts Communication Society
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    • v.9 no.1
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    • pp.27-44
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    • 1991
  • In this research, double-layered photoconductor consist of the carrier generation layer(CGL) of ${\varepsilon}$ type copper phthalocyanine thin film by an aqueous coating method and the carrier transport layer(CGL) of polyvinyl carbazol(PVK) by spin coating. We inverstigated effect of the surfactant solution and cathod electrolysis to the crystal type of ${\varepsilon}$-CuPc in CGL with TEM, SEM and X-ray diffraction spectroscopy and studied the mechanism of an aqueous coating for the preparation of CGL. The effect of the washing of CGL about the electrophotographic characteristics of the ${\varepsilon}$-CUPC/PVK double-layered photoconductors is studied also.

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Decrease of Distribution Volume of a Basic Drug in Rats of Experimental Renal Failure (신장해에 의한 염기성약물의 분포용적감소예와 그 기전)

  • 심창구
    • YAKHAK HOEJI
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    • v.27 no.1
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    • pp.21-28
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    • 1983
  • Distribution volume (Vd$_{ss}$ ) of a model basic drug, tetraethylammonium bromide (TEA) at a steady-state decreased sinificantly in glycerol and uranium-renal failure rats. Assuming carrier-mediated transport of TEA into tissues, the theoretical $Vd_{ss}$ of TEA decreases in an exponential way as the plasmal concentration of TEA increases. The relationship between $Vd_{ss}$ and plasma concentration of TEA in the experimental renal failure (ERF)-rats was similar. Therefore, the decrease in $Vd_{ss}$ of TEA in the ERF-rats seemed to be due to the saturation of the carrier system that are responsible for the tissue distribution of TEA, by the elevated plasma concentration of TEA in the ERF-rats. ERF was induced to rats with glycerol, folate, salicylate, uranium and gentamicin, respectively..

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A Study on The Revision of UCP600 concerning the Sea Transport Documents (UCP 600 해상운송서류(海上運送書類) 규정(規定)의 주요(主要) 개정사항(改正事項)에 관한 연구(硏究))

  • Park, Sae-Woon
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.35
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    • pp.71-98
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    • 2007
  • UCP 600 approved at the Banking Commission Meeting of ICC at the end of October, 2006 comes into effect from July 1, 2007. The main revision of the UCP 600 concerning the sea transport document are as follows. First, if the bill of lading contains an on-board-notation, with the date of shipment, the date stated in the on-board-notation will be deemed the date of shipment. Secondly, phrases "on its face" and "otherwise authenticated" should be eliminated. Thirdly, when an agent signs for or signs on behalf of the master, there is no longer a need for the name of master to be quoted. Fourthly, the terminology "loading on-board or shipped on a named vessel" is changed to "shipped on-board a named vessel." Fifthly, phrases "the rejection of the documents transported only by sail" is removed. Finally, new rule in UCP is the signing of a charter party bill of lading by the charterer or a named agent on behalf of the charterer. My assessment of the revision in UCP 600 is as follows: Because a freight forwarder transport document is a weaker form than a liner bill of lading as collateral, banks may need a secure measure as to protect themselves from such a weak collateral effect. we recognize that Such a weak collateral effect stemmed from the elimination of rules in UCP 500 article 30, and the admission of transport documents issued by the freight forwarder as long as any one besides carrier, shipper, and charterer satisfies the requirements of transport document clauses in UCP 600. Finally, I hope the Commentary on UCP 600 will serve to explain the ambiguities remaining in the new rules.

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