• Title/Summary/Keyword: Electron range

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Electron Tunneling and Electrochemical Currents through Interfacial Water Inside an STM Junction

  • Song, Moon-Bong;Jang, Jai-Man;Lee, Chi-Woo
    • Bulletin of the Korean Chemical Society
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    • v.23 no.1
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    • pp.71-74
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    • 2002
  • The apparent barrier height for charge transfer through an interfacial water layer between a Pt/Ir tip and a gold surface has been measured using STM technique. The average thickness of the interfacial water layer inside an STM junction was controlled by the amount of moisture. A thin water layer on the surface was formed when relative humidity was in the range of 10 to 80%. In such a case, electron tunneling through the thin water layer became the majority of charge transfers. The value of the barrier height for the electron tunneling was determined to be 0.95 eV from the current vs. distance curve, which was independent of the tip-sample distance. On the other hand, the apparent barrier height for charge transfer showed a dependence on tip-sample distance in the bias range of 0.1-0.5 V at a relative humidity of approximately 96%. The non-exponentiality for current decay under these conditions has been explained in terms of electron tunneling and electrochemical processes. In addition, the plateau current was observed at a large tip-sample distance, which was caused by electrochemical processes and was dependent on the applied voltage.

Diffusion Coefficients in $SF_6-Ar$ Gas used by MCS-BE Algorithm (MCS-BEq 알고리즘에 의한 $SF_6-Ar$ 혼합기체의 확산계수)

  • Kim, Sang-Nam
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.298-301
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    • 2006
  • This paper describes the electron energy distribution function characteristics in $SF_6-Ar$ gas calculated for range of E/N values from $50\sim700[Td]$ by the Monte Carlo simulation(MCS) and Boltzmann equation(BE) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by time of flight(TOF) method. In this dissertation the results of the combined experimental and theoretical studies designed to understand and predict the spatial growth and transport coefficients for electrons in $SF_6$ and $SF_6-Ar$ mixtures have described. The ionization and attachment coefficients in pure $SF_6$ and $SF_6-Ar$ mixtures have been calculated over the range of 10$SF_6$ molecule and for Ar atom proposed by other authors. The results obtained in this work will provide valuable information on the fundamental behaviors of electrons in weakly ionized gases and the role of electron attachment in the choice of better gases and unitary gas dielectrics or electro negative components in dielectric gas mixtures.

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The Analysis of Electron Transport Characteristics in $SiH_4$ Plasma ($SiH_4$ 플라즈마중의 전자수송특성 해석)

  • Lee, Hyoung-Yoon;Ha, Sung-Chul;Kim, Dae-Yeon
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.925-928
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    • 1998
  • In this paper, the electron transport characteristics in $SiH_4$ has been analysed over the E/N range $0.5{\sim}300[Td]$ and Pressure value 0.5, 1, 2.5 [Torr] by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity. diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50[Td] for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results of Boltzmann equation and Monte carlo simulation have been compared with experimental data by Pollock, Ohmori, cottrell and Walker.

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Analysis of electron transport properties in $SF_6$+He mixture gas used by MCS-BE (MCS-BE에 의한 $SF_6$+He 혼합기체의 전자수송특성 해석)

  • 하설철;송병두;유회영;김상남;백승권
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.4
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    • pp.359-364
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    • 2000
  • The paper describes the electron transport characteristics in SP$_{6}$+He gas calculated E/N values 0.1~700[Td] by the Monte Carlos simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters obtained by TOF method. This study gained the values of the electron swarm parameters such as the electron drift velocity the electron ionization or attachment coefficients longitudinal and transverse diffusion coefficients for SF$_{6}$+He gas at a range of E/N.E/N.

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Electron Transport Characteristics in $SiH_4$ by MCS-BEq (MCS-BEq에 의한 $SiH_4$ 전자수송특성(電子輸送特性))

  • Seong, Nak-Jin;Kim, Sang-Nam
    • Proceedings of the KIEE Conference
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    • 2005.10a
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    • pp.97-100
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    • 2005
  • This paper describes the electron transport characteristics in SiH4 has been analysed over the E/N range 0.5${\sim}$300[Td] and Pressure value 0.5, 1, 2.5 [Torr] by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50[Td] for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results of Boltzmann equation and Monte carlo simulation have been compared with experimental data by Pollock, Ohmori, cottrell and Walker.

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The study of electron transport coefficients in pure $CO_2$ by 2-term approximation of the Boltzmann equation (2항근사 볼츠만 방정식을 이용한 $CO_2$분자가스의 전자수송계수의 해석)

  • Jeon, Byung-Hoon;Kim, Ji-Yeon;Kim, Song-Gang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.164-167
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    • 2001
  • The electron transport coefficients, the electron drift velocity W, the longitudinal diffusion coefficient $ND_L$ and $D_L/{\mu}$, in pure $CO_2$ were calculated over the wide E/N range from 0.01 to 500 Td at 1 Torr by two-term approximation of the Boltzmann equation for determination of electron collision cross sections set and for quantitative characteristic analysis of $CO_2$ molecular gas. And for propriety of two-term approximation of Boltzmann equation analysis, the calculated results compared with the electron transport coefficients measured by Nakamura.

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Development of a neural network method for measuring the energy spectrum of a pulsed electron beam, based on Bremsstrahlung X-Ray

  • Sohrabi, Mohsen;Ayoobian, Navid;Shirani, Babak
    • Nuclear Engineering and Technology
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    • v.53 no.1
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    • pp.266-272
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    • 2021
  • In the pulsed electron beam generators, such as plasma focus devices and linear induction accelerators whose electron pulse width is in the range of nanosecond and less, as well as in cases where there is no direct access to electron beam, like runaway electrons in Tokamaks, measurement of the electron energy spectrum is a technical challenge. In such cases, the indirect measurement of the electron spectrum by using the bremsstrahlung radiation spectrum associated with it, is an appropriate solution. The problem with this method is that the matrix equation between the two spectrums is an ill-conditioned equation, which results in errors of the measured X-ray spectrum to be propagated with a large coefficient in the estimated electron spectrum. In this study, a method based on the neural network and the MCNP code is presented and evaluated to recover the electron spectrum from the X-ray generated by collision of the electron beam with a target. Multilayer perceptron network showed good accuracy in electron spectrum recovery, so that for the X-ray spectrum with errors of 3% and 10%, the network estimated the electron spectrum with an average standard error of 8% and 11%, on all of the energy intervals.

An analytical model for inversion layer electron mobility in MOSFET (MOS소자 반전층의 전자이동도에 대한 해석적 모델)

  • 신형순
    • Electrical & Electronic Materials
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    • v.9 no.2
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    • pp.174-179
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    • 1996
  • We present a new physically based analytical equation for electron effective mobility in MOS inversion layers. The new semi-empirical model is accounting expicitly for surface roughness scattering and screened Coulomb scattering in addition to phonon scattering. This model shows excellent agreement with experimentally measured effective mobility data from three different published sources for a wide range of effective transverse field, channel doping and temperature. By accounting for screened Coulomb scattering due to doping impurities in the channel, our model describes very well the roll-off of effective mobility in the low field (threshold) region for a wide range of channel doping level (Na=3.0*10$^{14}$ - 2.8*10$^{18}$ cm$^{-3}$ ).

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Electron Density Measurement of Inductively Coupled Plasma by Ar Gas Pressure (Ar 가스 압력에 따른 유도결합형 플라즈마의 전자 밀도 측정)

  • 이영환;김광수;조주웅;박대희
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.11
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    • pp.508-511
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    • 2003
  • In this paper, electrical characteristics of inductively coupled plasma in an electrodeless fluorescent lamp were investigated using a Langmuir probe with a variation of argon gas pressure. The RF output was applied in the range of 5 ∼ 50 (W) at 13.56 (MHz). The internal plasma voltage of the chamber and the probe current were measured while varying the supply voltage to the Langmuir probe in the range of -100 (V) ∼+100 (V). When the pressure of argon gas was increased, electric current was decreased. There was a significant electric current increase from l0W to 30 〔W〕. Also, when the RF power was increased, electron density was increase. This implies that this method can be used to find an optimal RF rower for efficient light illumination in an electrodeless fluorescent lamp.

Characteristics of Thermally Stimulated Current in the ZnO varister (ZnO 바리스터의 TSC 특성)

  • 안용모;이성일;이상석;박춘배;이준용
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1989.06a
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    • pp.101-104
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    • 1989
  • Thermal Electet of the Zinc Oxide varistor has been studied in the temperature range of -130~200[$^{\circ}C$] and the electric field of 6[kV/m]. It appears that there are four peaks of thermally stimulated current; $\alpha$, $\beta$, ${\gamma}$ and $\delta$ spectra appearing at the temperature range of 160, 130, 20 and -30[$^{\circ}C$], respectively. It seems that the origin of $\alpha$, $\beta$, ${\gamma}$ and $\delta$ peaks are associated with the depolarization of donor ions in the depletion layer, the detrapping of trapped electron in the surface, the detrapping of trapped electron in the donor level and the detrapping of trapped electron between grain and intergranular, respectively.

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