• Title/Summary/Keyword: Interface Layer

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Impedance spectroscopy analysis of polymer light emitting diodes with the LiF buffer layer at the cathode/organic interface (LiF 음극 버퍼층을 사용한 폴리머의 효율 향상에 관한 임피던스 분석)

  • Kim, H.M.;Jang, K.S.;Yi, J.;Sohn, Sun-Young;Park, Kuen-Hee;Jung, Dong-Geun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.277-278
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    • 2005
  • Admittance Spectroscopic analysis was applied to study the effect of LiF buffer layer and to model the equivalent circuit for poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV)-based polymer light emitting diodes (PLEDs) with the LiF cathode buffer layer. The single layer device with ITO/MEH-PPV/Al structure can be modeled as a simple parallel combination of resistor and capacitor. Insertion of a LiF layer at the Al/MEH-PPV interface shifts the highest occupied molecular orbital level and the vacuum level of the MEH-PPV layer as a result the barrier height for electron injection at the Al/MEH-PPV interface is reduced. The admittance spectroscopy measurement of the devices with the LiF cathode buffer layer shows reduction in contact resistance ($R_c$), parallel resistance ($R_p$) and increment in parallel capacitance ($C_p$).

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Role of ${\alpha}-Al_2O_3$ buffer layer in $Ba-ferrite/SiO$ magnetic thin films (Ba-페라이트/$SiO_2$ 자성박막에서 ${\alpha}-Al_2O_3$ buffer 층의 역할)

  • Cho, Tae-Sik;Jeong, Ji-Wook;Kwon, Ho-Jun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.267-270
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    • 2003
  • We have studied the interfacial diffusion phenomena and the role of ${\alpha}-Al_2O_3$ buffer layer as a diffusion barrier in the $Ba-ferrite/SiO_2$ magnetic thin films for high-density recording media. In the interface of amorphous Ba-ferrite ($1900-{\AA}-thick)/SiO_2$ thin film during annealing, the interfacial diffusion started to occur at ${\sim}700^{\circ}C$. As the annealing temperature increased up to $800^{\circ}C$, the interfacial diffusion abruptly proceeded resulting in the high interface roughness and the deterioration of the magnetic properties. In order to control the interfacial diffusion at the high temperature, we introduced ${\alpha}-Al_2O_3$ buffer layer ($110-{\AA}-thick$) in the interface of $Ba-ferrite/SiO_2$ thin film. During the annealing of $Ba-ferrite/{\alpha}-Al_2O_3/SiO_2$ thin film even at ${\sim}800^{\circ}C$, the interface was very smooth. The smooth interface of the film was also clearly shown by the cross-sectional FESEM. The magnetic properties, such as saturation magnetization 3nd intrinsic coercivity, were also enhanced, due to the inhibition of interfacial diffusion by the ${\alpha}-Al_2O_3$ buffer layer. Our study suggests that the ${\alpha}-Al_2O_3$ buffer layer act as a useful interfacial diffusion barrier in the $Ba-ferrite/SiO_2$ thin films.

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A Study on the Implementation of PC Interface for Packet Terminal of ISDN (ISDN 패킷 단말기용 PC 접속기 구현에 관한 연구)

  • 조병록;박병철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.12
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    • pp.1336-1347
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    • 1991
  • In this paper, The PC interface for packet terminal of ISDN is designed and implemented in order to build packet communication networks which share computer resources and exchange informations between computer in the ISDN environment. The PC interface for packet terminal of ISDN constitutes S interface handler part which controls functions of ISDN layer1 and layer 2, constitutes packet handler part which controls services of X.25 protocol in the packet level.Where, The function of ISDN layer1 provides rules of electrical and mechanical characteristics, services for ISDN layer 2. The function of ISDN layer 2 provides function of LAPD procedure, services for X.25 The X.25 specifies interface between DCE and DTE for terminals operrating in the packet mode. The S interface handler part is orfanized by Am 79C30 ICs manufactured by Advanecd Micro Devices. ISDN packet handler part is organiged by AmZ8038 for FIFO for the purpose of D channel. The common signal procedure for D channel is controlled by Intel's 8086 microprocessor. The S interface handler part is based on ISDN layer1,2 is controlled by mail box in order to communicate between layers. The ISDN packet handler part is based on module in the X.25 lebel. The communication between S interface handler part and ISDN packet handler part is organized by interface controller.

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Control of Grain Size of PZT Thin Film through Seed Layers (Seed Layer를 통한 PZT 박막의 결정립 크기 조절)

  • Kim, Tae-Ho;Kim, Ji-Young;Lee, In-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.273-278
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    • 2000
  • In order to study effects of interface layers between PZT films and electrodes for MFM(Metal-Ferroelectric-Metal) structure capacitors, we have fabricated the capacitors with the Pt/PZT/interface-layer/Pt/$TiO_2/SiO_2/Si$ structure. $PT(PbTiO_3)$ interface layers were formed by sol-gel deposition and PbO, $ZrO_2$ and $TiO_2$ thin layers were deposited by reactive sputtering. $TiO_2$ interface layers result in the finest grains of PZT films compared to $PbO_2$ and $ZrO_2$ layers. On the other hand, PT interface layers result in improved morphology of PZT films and do not significantly change ferroelectric properties. It is also observed that seed layers at the middle and top of PZT films do not give significant effects on grain size but the PT seed layer at the interface between the bottom electrode and the PZT films results in the small grain size.

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On Oil-Water Interface of Oil Layer Contained in Tandem Oil Fences (이중유벽 사이에 가두어진 기름층의 거동특성)

  • Doh D.H.;Hyun B.S.;Choi S.H.;Hong S.H.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.3 no.1
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    • pp.25-34
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    • 2000
  • A panoramic-PIV technique is employed to characterize the travelling tip vortices and the profile of oil-water Interface in the tandem fence arrangement. Instantaneous as well as time-averaged velocity profiles of the water layer close to the interface were obtained to evaluate the possibility of measuring the shear stress distribution on oil-water interface. It was proven that the present technique could provide some qualify data precise enough to resolve detailed flow structures inside a shear layer formed on oil-water interface provided it is nearly stationary.

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High-Efficiency a-Si:H Solar Cell Using In-Situ Plasma Treatment

  • Han, Seung Hee;Moon, Sun-Woo;Kim, Kyunghun;Kim, Sung Min;Jang, Jinhyeok;Lee, Seungmin;Kim, Jungsu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.230-230
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    • 2013
  • In amorphous or microcrystalline thin-film silicon solar cells, p-i-n structure is used instead of p/n junction structure as in wafer-based Si solar cells. Hence, these p-i-n structured solar cells inevitably consist of many interfaces and the cell efficiency critically depends on the effective control of these interfaces. In this study, in-situ plasma treatment process of the interfaces was developed to improve the efficiency of a-Si:H solar cell. The p-i-n cell was deposited using a single-chamber VHF-PECVD system, which was driven by a pulsed-RF generator at 80 MHz. In order to solve the cross-contamination problem of p-i layer, high RF power was applied without supplying SiH4 gas after p-layer deposition, which effectively cleaned B contamination inside chamber wall from p-layer deposition. In addition to the p-i interface control, various interface control techniques such as thin layer of TiO2 deposition to prevent H2 plasma reduction of FTO layer, multiple applications of thin i-layer deposition and H2 plasma treatment, H2 plasma treatment of i-layer prior to n-layer deposition, etc. were developed. In order to reduce the reflection at the air-glass interface, anti-reflective SiO2 coating was also adopted. The initial solar cell efficiency over 11% could be achieved for test cell area of 0.2 $cm^2$.

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An Implementation of Socket Interface for TOEs (TOE를 위한 소켓 인터페이스의 구현)

  • Son, Sung-Hoon
    • Journal of Korea Multimedia Society
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    • v.8 no.11
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    • pp.1472-1482
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    • 2005
  • In this paper, we propose a socket interface layer for large-scale multimedia servers that adopt TCP/IP Offload Engines (TOE). In order to provide legacy network applications with binary level compatibility, the socket interface layer intercepts all socket-related system calls to forward to either TOE or legacy TCP/IP Protocol stack. The layer is designed and implemented as a kernel module in Linux. The layer is located between BSD socket layer and INET socket layer, and passes the application's socket requests to INET socket layer or TOE. The layer provides multimedia servers and web servers with the following features: (1) All standard socket APIs and file I/O APIs that are supported (2) Support for binary level compatibility of existing socket programs (3) Support for TOE and legacy Ethernet NICs at the same time.

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A Polymer Interface for Varying Electron Transfer Rate with Electrochemically Formed Gold Nanoparticles from Spontaneously Incorporated Tetrachloroaurate(III) Ions

  • Song, Ji-Seon;Kang, Chan
    • Bulletin of the Korean Chemical Society
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    • v.28 no.10
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    • pp.1683-1688
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    • 2007
  • This paper presents a novel simple method for introducing gold nanoparticles in a poly(4-vinylpyridine) (PVP) polymer layer over a glassy carbon (GC) electrode with the aim of forming a tunable electrochemical interface against a cationic ruthenium complex. Initially, AuCl4 ? ions were spontaneously incorporated into a polymer layer containing positively charged pyridine rings in an acidic media by ion exchange. A negative potential was then applied to electrochemically reduce the incorporated AuCl4 ? ions to gold nanoparticles, which was confirmed by the FE-SEM images. The PVP layer with an appropriate thickness over the electrode blocked electron transfer between the electrode and the solution phase for the redox reactions of the cationic Ru(NH3)6 2+ ions. However, the introduction of gold nanoparticles into the polymer layer recovered the electron transfer. In addition, the electron transfer rate between the two phases could be tuned by controlling the number density of gold nanoparticles.

Analysis of Stresses Induced in a Polymer Coating Layer due to Temperature Change (온도변화에 대한 고분자 코팅 층에 발생하는 응력 해석)

  • 박명규;이상순;서창민
    • Journal of Ocean Engineering and Technology
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    • v.17 no.6
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    • pp.72-76
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    • 2003
  • This paper deals with the stress singularity developed in a polymer layer that is coated to a concrete surface, due to temperature change. The boundary element method is employed to investigate the behavior of interface stresses. The polymeric layer is assumed to be a linear viscoelastic material, and is thermorheologically simple. The order of the singularity is obtained, numerically, for a given viscoelastic model. Numerical results exhibit the relaxation of interface stresses, and large gradients are observed in the vicinity of the free surface. Results show that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model.

The effects of TCO/p-layer Interface on Amorphous Silicon Solar Cell (비정질 실리콘 태양전지에서 TCO/p층 계면 특성의 영향)

  • Ji, I.H.;Suh, S.T.;Choi, B.S.;Hong, S.M.
    • Solar Energy
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    • v.8 no.1
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    • pp.68-73
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    • 1988
  • In the glass/TCO/p-i-n a-Si/Al type of amorphous silicon solar cell, the effects on solar cell efficiency and metastability for the various kinds of TCO analyzed by SAM and ESCA, which was used to measure the diffusion profiles of In and Sn and the Fermi energy shifts in the TCO/p interface respectively. Indium which diffused into a-Si p-layer did not have any significant effects on the Fermi level shift of p-layer when the content of $B_2H_6/SiH_4$ in p-layer was at 1 gas%. The cell fabricated on $SnO_2$ turned out to have the best cell photovoltaic characteristics. ITO fabricated by electron beam deposition system, which was shown to have the greatest rate of diffusion of Indium in ITO/p interface produced the worst metastability among the cells tested.

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