• 제목/요약/키워드: Interfacial electronic structure

검색결과 61건 처리시간 0.026초

Interfacial Effects in Filled and Reinforced Polymeric Composites

  • Xie, Hengkun
    • E2M - 전기 전자와 첨단 소재
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    • 제11권10호
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    • pp.24-31
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    • 1998
  • Interfacial effect in polymetric composites have been studied extensively. This report deals mainly with the effects of interfacial space charge and interface structure. A model for the dynamic process of interfacial space charge accumulation is proposed. The new model might interpret some interface phenomena which is difficult to be explained in terms of traditional Maxwell-Wagner theory. An interface structure is also presented, by which the importance of surface treatment of glass Fiber for improving the properties of FRP could be well understood.

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Interfacial Electronic Structure of Bathocuproine and Al: Theoretical Study and Photoemission Spectroscopy

  • Lee, Jeihyun;Kim, Hyein;Shin, Dongguen;Lee, Younjoo;Park, Soohyung;Yoo, Jisu;Jeong, Junkyeong;Hyun, Gyeongho;Jeong, Kwangho;Yi, Yeonjin
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.169-169
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    • 2014
  • Interfacial electronic structure of bathocuproine and Al was investigated using in-situ photoemission spectroscopy and density functional theory (DFT) calculations. Bathocuproine is used for exciton blocking and electron transport material in organic photovoltaics and Al is typical cathode material. When thin thickness of Al was thermally evaporated on BCP, gap states were observed by ultraviolet photoemission spectroscopy. The closest gap state yielded below 0.3 eV from Fermi level. By x-ray photoemission spectroscopy, interaction of Al with nitrogen of BCP was observed. To understand the origin of gap states, DFT calculation was carried out and gap states was verified with successive calculation of interaction of Al and nitrogen of BCP. Furthermore, emergency of another state above Fermi level was observed. Remarkable reduction of electron injection barrier between Al and BCP, therefore, is possible.

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Effect of Sputtering Power on the Change of Total Interfacial Trap States of SiZnSnO Thin Film Transistor

  • Ko, Kyung-Min;Lee, Sang Yeol
    • Transactions on Electrical and Electronic Materials
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    • 제15권6호
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    • pp.328-332
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    • 2014
  • Thin film transistors (TFTs) with an amorphous silicon zinc tin oxide (a-2SZTO) channel layer have been fabricated using an RF magnetron sputtering system. The effect of the change of excitation electron on the variation of the total interfacial trap states of a-2SZTO systems was investigated depending on sputtering power, since the interfacial state could be changed by changing sputtering power. It is well known that Si can effectively reduce the generation of the oxygen vacancies. However, The a-2SZTO systems of ZTO doped with 2 wt% Si could be degraded because the Si peripheral electron belonging to a p-orbital affects the amorphous zinc tin oxide (a-ZTO) TFTs of the s-orbital overlap structure. We fabricated amorphous 2 wt% Si-doped ZnSnO (a-2SZTO) TFTs using an RF magnetron sputtering system. The a-2SZTO TFTs show an improvement of the electrical property with increasing power. The a-2SZTO TFTs fabricated at a power of 30 W showed many of the total interfacial trap states. The a-2SZTO TFTs at a power of 30 W showed poor electrical property. However, at 50 W power, the total interfacial trap states showed improvement. In addition, the improved total interfacial states affected the thermal stress of a-2SZTO TFTs. Therefore, a-2SZTO TFTs fabricated at 50 W power showed a relatively small shift of threshold voltage. Similarly, the activation energy of a-2SZTO TFTs fabricated at 50 W power exhibits a relatively large falling rate (0.0475 eV/V) with a relatively high activation energy, which means that the a-2SZTO TFTs fabricated at 50 W power has a relatively lower trap density than other power cases. As a result, the electrical characteristics of a-2SZTO TFTs fabricated at a sputtering power of 50 W are enhanced. The TFTs fabricated by rf sputter should be carefully optimized to provide better stability for a-2SZTO in terms of the sputtering power, which is closely related to the interfacial trap states.

CNTs Electric Field Enhancement of CIGS Solar Cells

  • 한성환
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.67-67
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    • 2011
  • Compound semiconductor/CNTs composites have shown considerably improved efficiency improvement in photovoltaic devices, which is often attributed to two different factors. One is the formation of efficient electronic energy cascade structures. The other effect of CNTs on the performance of photovoltaic devices is the decrement of interfacial resistance. The interfacial resistances at n-type/ p-type materials and/or n-type materials/TCO electrode are reduced by an outstanding electrical property of CNTs. In addition to the effects of CNTs, we report the third reason for increment of efficiency in photovoltaic devices by CNT's well-known electrical field enhancement effects. The improved ${\beta}$ values in reverse-FE currents of CIGS electrode with SWNTs layers indicate the enhancement of electrical field in photovoltaic devices, which implies the acceleration of the electron transfer rate in the cell. Due to the formation of an efficient electronic energy cascade structure and the decrease of the interfacial resistance as well as the improvement of the electrical field in the photovoltaic devices, the power conversion efficiency of electrochemically deposited superstrate-type CIGS solar cells was increased 24.3% in the presence of SWNTs and showed 10.40% conversion efficiency.

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광검출기용 다결정 실리콘 박막의 전도특성 분석을 통한 결정립계의 모형화 (Modelling of Grain Boundary in Polysilicon Film for Photodetector Through Current-Voltage Analysis)

  • 이재성
    • 한국전기전자재료학회논문지
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    • 제33권4호
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    • pp.255-262
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    • 2020
  • Grain boundaries play a major role in determining device performance, particularly of polysilicon-based photodetectors. Through the post-annealing of as-deposited polysilicon and then, the analysis of electric behavior for a metal-polysilicon-metal (MSM) photodetector, we were able to identify the influence of grain boundaries. A modified model of polysilicon grain boundaries in the MSM structure is presented, which uses a crystalline-interfacial layer-SiOx layer- interfacial layer-crystalline system that is similar to the Si-SiO2 system in MOS device. Hydrogen passivation was achieved through a hydrogen ion implantation process and was used to passivate the defects at both interfacial layers. The thin SiOx layer at the grain boundary can enhance the photosensitivity of an MSM photodetector by decreasing the dark current and increasing the light absorption.

Fabrication of Novel Thin Film Diode with Multi-step Anodic Oxidation and Post Heat-treatment

  • Hong, Sung-Jei;Lee, Chan-Jae;Moon, Dae-Gyu;Kim, Won-Keun;Han, Jeong-In
    • Transactions on Electrical and Electronic Materials
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    • 제3권4호
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    • pp.27-31
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    • 2002
  • Thin film diode with reliable interfacial structure was fabricated by using multi-step anodic oxidation. The thickness of the oxide layer was preciously controlled with anodic voltage. Also, interfacial structure between oxide layer and top electrode was improved by applying post heat-treatment. The thin film diode showed symmetric and stable I-V characteristics after the post heat-treatment.

InSb MIS구조에서의 계면의 전기적 특성 평가 (Characterization of interfacial electrical properties in InSb MIS structure)

  • 이재곤;최시영
    • 센서학회지
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    • 제5권6호
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    • pp.60-67
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    • 1996
  • 저온 remote PECVD $SiO_{2}$막을 이용하여 제조된 InSb MIS구조에서의 계면의 전기적 특성에 대하여 연구하였다. $105^{\circ}C$에서 증착시킨 $SiO_{2}$막을 이용한 MIS구조의 중간 에너지 대역폭에서의 계면상태밀도가 $1{\sim}2{\times}10^{11}\;cm^{-2}eV^{-1}$으로 평가되었다. 그러나, $105^{\circ}C$이상의 고온에서 제조된 MIS소자의 계면에는 다량의 계면준위 및 트랩 준위가 존재하였다. G-V측정으로부터 계산된 계면준위들의 시상수는 $10^{-4}{\sim}10^{-5}\;sec$였으며, 증착온도가 증가할수록 트랩밀도가 증가하여 C-V특성곡선의 이력특성이 증대되었다.

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TSC 기법에 의한 고분자 절연재료의 열화특성 연구 (A Study on the Degradation Characteristics of Polymer Insulating Materials using TSC Technique)

  • 박재세;성낙진
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1995년도 추계학술대회 논문집
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    • pp.285-288
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    • 1995
  • In this Study, it worked to get the degradation characteristics of polymer insulating materials using TSC technique. So, it prepared epoxy composities with sample, the TSC spectroscopy was applied to investigate the influence of interfacial deformation due to inorganic filler and treatments of coupling agents on the network structure and the electrical properties of epoxy composites.

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Properties of Dy-doped $La_2O_3$ buffer layer for Fe-FETs with Metal/Ferroelectric/Insulator/Si structure

  • Im, Jong-Hyun;Kim, Kwi-Jung;Jeong, Shin-Woo;Jung, Jong-Ill;Han, Hui-Seong;Jeon, Ho-Seung;Park, Byung-Eun
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.140-140
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    • 2009
  • The Metal-ferroelectric-semiconductor (MFS) structure has superior advantages such as high density integration and non-destructive read-out operation. However, to obtain the desired electrical characteristics of an MFS structure is difficult because of interfacial reactions between ferroelectric thin film and Si substrate. As an alternative solution, the MFS structure with buffer insulating layer, i.e. metal-ferroelectric-insulator-semiconductor (MFIS), has been proposed to improve the interfacial properties. Insulators investigated as a buffer insulator in a MFIS structure, include $Ta_2O_5$, $HfO_2$, and $ZrO_2$ which are mainly high-k dielectrics. In this study, we prepared the Dy-doped $La_2O_3$ solution buffer layer as an insulator. To form a Dy-doped $La_2O_3$ buffer layer, the solution was spin-coated on p-type Si(100) wafer. The coated Dy-doped $La_2O_3$ films were annealed at various temperatures by rapid thermal annealing (RTA). To evaluate electrical properties, Au electrodes were thermally evaporated onto the surface of the samples. Finally, we observed the surface morphology and crystallization quality of the Dy-doped $La_2O_3$ on Si using atomic force microscopy (AFM) and x-ray diffractometer (XRD), respectively. To evaluate electrical properties, the capacitance-voltage (C-V) and current density-voltage (J-V) characteristics of Au/Dy-doped La2O3/Si structure were measured.

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