• Title/Summary/Keyword: Hole density

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Development of Equivalent Magnetic Circuit Network Method for 3-D Eddy Current Analysis (3차원 와전류 해석을 위한 등가자기회로망법의 개발)

  • Hur, Jin;Hong, Jung-Pyo;Hyun, Dong-Seok
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.693-695
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    • 2001
  • A computational method for the 3 dimensional electro-magnetic induction problems has been developed. The proposed method is capable of modeling the eddy current and analyzing its characteristics using only scalar potential. A benchmark model of asymmetrical conductor with a hole is analyzed to verify the application of the developed method. The calculated value of magnetic flux density are compared with the measured value, and the results indicate that the developed method is valid.

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Hall-effect properties of single crystal semiconductor P-GaSe dopes with $Er^{3+}$ (Erbium 도핑된 p-GaSe 단결정의 홀 효과 특성)

  • Lee, Woo-Sun;Oh, Guem-Kon;Chung, Young-Ho;Jung, Chang-Soo;Son, Kyeong-Choon;Kim, Nam-Oh
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.726-728
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    • 1998
  • Optical and electrical properties of GaSe:$Er^{3+}$ single crystals grown by the Bridgeman technique was been investigated by using optical absorption and Hall-effect measurements. The Hall coefficients were measured by using a high impedance electrometer in the temperature range from 360K to 150K. The temperature dependence of hole concentration shows the characteristic of a partially compensated p-type semiconductor. carrier density($N_H$) of GaSe doped with Erbium was measured about $3.25{\times}10^{16}\;[cm^{-3}}$ at temperature 300K, which was high than undoped specimen. Photon energy gap ($E_{gd}$) was measured about 1.7geV.

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Transport phenomena of a-Se:As thin film for digital X-ray Conversion Material (디지털 X-선 변환물질을 위한 비소(As) 첨가 비정질 셀레늄(a-Se) 박막의 수송현상)

  • Park, Chang-Hee;Kim, Jae-Hyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.282-283
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    • 2006
  • The transport phenomena of arsenic (As) doped amorphous selenium(a-Se:As) thin film for digital X-ray conversion material has been reported. The effect of As addition on the carrier mobility and recombination lifetime in a-Se:As sample has been measured using the moving photo-carrier grating (MPG) technique. An Increase in hole mobility and recombination was observed when 0.3% arsenic, was added into a-Se sample, whereas electron mobility decrease with arsenic addition due to the defect density. The fabricated a-Se:03% As device exhibited the highest X-ray sensitivity.

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Property variations of undoped ZnO thin films with deposition conditions (증착조건에 따른 undoped ZnO 박막의 특성 변화)

  • Nam, Hyoung-Gin;Lee, Kyu-Hwang;Cho, Nam-Ihn
    • Journal of the Semiconductor & Display Technology
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    • v.7 no.3
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    • pp.51-54
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    • 2008
  • In this study, we investigated variations in undoped ZnO thin film properties with working pressure, $O_2$/Ar ratio, and annealing ambient. Higher vacuum pressure during deposition was observed to bring about slower growth rate resulting in samples with better crystallinity as well as hole generation efficiency through formation of shallower oxygen interstitial. Given that $O_2$/Ar ratio is greater than unity, O provided from the ambient to ZnO during annealing was found to preferably situate at interstitial sites. When He was used for the second annealing, significant changes were not observed. On the other hand, O ambient caused increased density of oxygen interstitial, thereby making the film more intrinsic-like high resistivity ZnO.

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Dependence of Self-heating Effect on Width/Length Dimension in p-type Polycrystalline Silicon Thin Film Transistors

  • Lee, Seok-Woo;Kim, Young-Joo;Park, Soo-Jeong;Kang, Ho-Chul;Kim, Chang-Yeon;Kim, Chang-Dong;Chung, In-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.505-508
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    • 2006
  • Self-heating induced device degradation and its width/length (W/L) dimension dependence were studied in p-type polycrystalline silicon (poly-Si) thin film transistors (TFTs). Negative channel conductance was observed under high power region of output curve, which was mainly caused by hole trapping into gate oxide and also by trap state generation by self-heating effect. Self-heating effect became aggravated as W/L ratio was increased, which was understood by the differences in heat dissipation capability. By reducing applied power density normalized to TFT area, self-heating induced degradation could be reduced.

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Extreme baking effect of interlayer on PLED's performance

  • Kim, Mu-Gyeom;Kim, Sang-Yeol;Lee, Tae-Woo;Park, Sang-Hun;Park, Jong-Jin;Pu, Lyong-Sun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1775-1778
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    • 2006
  • Through baking process on an interlayer, known as hole transporting layer, varying baking temperature up to 300 degree, which is considered as extremely high for polymer light emitting device (PLED) system, we found interesting relationship between packing density and morphology affecting device performance. Granular morphology shows that as temperature increases, grain size is getting smaller to pack closely and make interlayer harden. Such denser interlayer has temperature dependency of its own mobility, even without clear evidence of degradation of material itself. Its fact proven in a single film also reflects on multilayered PLED's performance like IVL, efficiency, lifetime. It's found that, especially, to enhance lifetime is related with thermal stability of interlayer and its mobility dependency to meet better charge balance. Therefore, it gives us understanding not only baking effect of interlayer, but also material & device designing guide to enhance lifetime.

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Nature of Surface and Bulk Defects Induced by Epitaxial Growth in Epitaxial Layer Transfer Wafers

  • Kim, Suk-Goo;Park, Jea-Gun;Paik, Un-Gyu
    • Transactions on Electrical and Electronic Materials
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    • v.5 no.4
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    • pp.143-147
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    • 2004
  • Surface defects and bulk defects on SOI wafers are studied. Two new metrologies have been proposed to characterize surface and bulk defects in epitaxial layer transfer (ELTRAN) wafers. They included the following: i) laser scattering particle counter and coordinated atomic force microscopy (AFM) and Cu-decoration for defect isolation and ii) cross-sectional transmission electron microscope (TEM) foil preparation using focused ion beam (FIB) and TEM investigation for defect morphology observation. The size of defect is 7.29 urn by AFM analysis, the density of defect is 0.36 /cm$^2$ at as-direct surface oxide defect (DSOD), 2.52 /cm$^2$ at ox-DSOD. A hole was formed locally without either the silicon or the buried oxide layer (Square Defect) in surface defect. Most of surface defects in ELTRAN wafers originate from particle on the porous silicon.

Numerical Simulation for Model Gas Turbine Combustor (모형 가스터빈 연소기의 수치해석적 연구)

  • 김태한;최병륜
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.7
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    • pp.1789-1798
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    • 1994
  • This paper aimed for numerical simulation of complicated gas turbine combustor with swirler. For the convenience of numerical analysis, fuel nozzle and air linear hole areas of secondary and dilution zone, which are issued to jet stream, were simplified to equivalent areas of annular type. In other to solve these problems, imaginary source terms which are corresponded to supplied fuel amount were added to those of governing equation. Chemical equilibrium model of infinite reaction rate and $k-{\epsilon}-g$ model with the consideration of density fluctuation were applied. As the result, swirl intensity contributed to mixing of supplied fuel and air, and to speed up the flame velocity than no swirl condition. Temperature profiles were higher than experimental results at the upstream and lower at the downstream, but total energy balance was accomplished. As these properties showed the similar trend qualitatively, simplified simulation method was worth to apply to complicated combustor for predicting combustion characteristics.

Dual Contrast EPI by Use of a Key Hole Technique

  • Jung, Kwan-Jin
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.113-113
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    • 2001
  • Purpose: In the gradient echo EPI the conventional T2*-weighted image is poor in signal as well distorted by the field inhomogeneity. By acquiring a proton density image in addition to th T2*-weighted image at the same scan, the fMRI processing can be improved. Method: The central region of the k space is acquired twice at different time points after th RF pulse while acquiring the other regions onc as described in Fig. 1. In Fig. 1 the segment numbers are chronological. Then, we can get two images of different contrast by interleaving th central region in the k space as done in the dua contrast FSE.

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Hot-Carrier-Induced Degradation in Submicron MOS Transistors (Submicron MOS 트랜지스터의 뜨거운 운반자에 의한 노쇠현상)

  • 최병진;강광남
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.7
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    • pp.780-790
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    • 1988
  • We have studied the hot-carrier-induced degradation caused by the high channel electric field due to the decrease of the gate length of MOSFET used in VLSI. Under DC stress, the condition in which maximum substrate current occures gave the worst degradation. Under AC dynamic stress, other conditions, the pulse shape and the falling rate, gave enormous effects on the degradation phenomena, especially at 77K. Threshold voltage, transconductance, channel conductance and gate current were measured and compared under various stress conditions. The threshold voltage was almost completely recovered by hot-injection stress as a reverse-stress. But, the transconductance was rapidly degraded under hot-hole injection and recovered by sequential hot-electron stress. The Si-SiO2 interface state density was analyzed by a charge pumping technique and the charge pumping current showed the same trend as the threshold voltage shift in degradation process.

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