• Title/Summary/Keyword: shubnikov-de haas oscillations (SdH)

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Shubnikov-de Haas Oscillations in an Individual Single-Crystalline Semimetal Bismuth Nanowire (단결정 반금속 비스무스 단일 나노선의 Shubnikov-de Haas 진동)

  • Kim, Jeong-Min;Ham, Jin-Hee;Shim, Woo-Young;Lee, Kyoung-Il;Jeon, Kye-Jin;Jeung, Won-Young;Lee, Woo Young
    • Korean Journal of Materials Research
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    • v.18 no.2
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    • pp.103-106
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    • 2008
  • The magneto-transport properties of an individual single crystalline Bi nanowire grown by a spontaneous growth method are reported. A four-terminal device based on an individual 400-nm-diameter nanowire was successfully fabricated using a plasma etching technique that removed an oxide layer that had formed on the surface of the nanowire. Large transverse ordinary magnetoresistance (1401%) and negative longitudinal ordinary magnetoresistance (-38%) were measured at 2 K. It was observed that the period of Shubnikov-de Haas oscillations in transverse geometry was $0.074^{T-1}$, $0.16^{T-1}$ and $0.77^{T-1}$, which is in good agreement with those of bulk Bi. However, it was found that the period of SdH oscillation in longitudinal geometry is $0.24^{T-1}$, which is larger than the value of $0.16^{T-1}$ reported for bulk Bi. The deviation is attributable to the spatial confinement arising from scattering at the nanowire surface boundary.

Electro-magnetic properties of GaAs/AlGaAs quantum wires (GaAs/AlGaAs 양자세선의 전자기적 특성)

  • 이주인;서정철;이창명;임재영
    • Journal of the Korean Vacuum Society
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    • v.10 no.2
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    • pp.262-266
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    • 2001
  • We have presented the electrical properties of the quantum wire fabricated by split gate on GaAs/AlGaAs heterostructures by using the Shubnikov de Haas oscillation and quantum Hall effect measurements. We observed the 1D properties of the sample as increasing gate voltage. The misfit between quantum Hall plateau and minima in Shubnikov do Haas oscillations are interpreted as Landauer-B$"{u}$ tikker formula based on the edge state transport.port.

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Effects of barrier height on electron scattering mechanisms in $\delta-doped$ InAlAs/InGaAs/InAlAs Heterostructures

  • Park, H.S.;Vang, S.J.;Kim, J.I.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.955-959
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    • 2004
  • The effects of conduction band offset on 2 dimensional electron gas (2DEG) in N-InAlAs(AlAsSb)/InGaAs/InAlAs (AlAsSb) metamorphic heterostructures (MMHS) are studied. A combination of the Shubnikov-deHaas oscillations and the Hall measurements is used to investigate the electron transport properties of these structures. The mobility in the second subband is higher than that in the first subband in all heterostructures. This is attributed to the fact that electrons in the first subband we, on average, closer to the interface and are therefore scattered more strongly by ionized impurities. The results suggest that intersubband scattering rate is more dominant in structures with higher conduction band offset whereas alloy scattering is found to be more dominant in the higher band offset system.

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The Periods of Shubnikov-de Haas Oscillations in an Individual Single-Crystalline Bi Nanowire Grown by On-Film Formation of Nanowires

  • Kim, Jeong-Min;Ham, Jin-Hee;Lee, Seung-Hyun;Lee, Woo-Young
    • Proceedings of the Korean Magnestics Society Conference
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    • 2010.06a
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    • pp.80-81
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    • 2010
  • We observed period of SdH oscillation in an individual Bi nanowire with the transverse and longitudinal magnetic fields along the axis of the nanowire grown by OFF-ON. Our results provide good qualitative description of the cyclotron behavior of the single-crystalline Bi nanowire in the ballistic regime.

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Electron mobility and low temperature magnetoresistance effect in $Si/Si_{1-x}Ge_x$ quantum well devices ($Si/Si_{1-x}Ge_x$Quantum Well 디바이스에서의 전자이동도 및 저온 자기저항효과)

  • 김진영
    • Journal of the Korean Vacuum Society
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    • v.8 no.2
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    • pp.148-152
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    • 1999
  • the low temperature magnetoresistance effect, electron mobilities, and 2 Dimensional electron Gases (2DEG) properties were investigated in $Si/Si_{1-x}Ge_x$ quantum well devices. N-type $Si/Si_{1-x}Ge_x$ structures were fabricated by utilizing a gas source Molecular Beam Epitaxy (GSMBE). Thermal oxidation was carried out in a dry O atmosphere at $700^{\circ}C$ for 7 hours. Electron mobilities were measured by using a Hall effect and a magnetoresistant effect at low temperatures down to 0.4K. Pronounced Shubnikov-de Haas (SdH) oscillations were observed at a low temperature showing two dimensional electron gases (2DEG) in s tensile strained Si quantum well. The electron sheet density (ns) of $1.5\times10^{12}[\textrm{cm}^{-2}]$ and corresponding electron mobility of 14200 $[\textrm{cm}^2V^{-1}s^{-1}]$ were obtained at a low temperature of 0.4K from $Si/Si_{1-x}Ge_x$ structures with thermally grown oxides.

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Low temperature electron mobility property in Si/$Si_{1-x}Ge_{x}$ modulation doped quantum well structure with thermally grown oxide

  • Kim, Jin-Young
    • Journal of Korean Vacuum Science & Technology
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    • v.4 no.1
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    • pp.11-17
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    • 2000
  • The low temperature electron mobilities were investigated in Si/$Si_{1-x}Ge_{x}$ modulation Doped (MOD) quantum well structure with thermally grown oxide. N-type Si/$Si_{1-x}Ge_{x}$ structures were fabricated by a gas source MBE. Thermal oxidation was carried out in a dry $O_2$ atmosphere at $700^{\circ}C$ for 7 hours. Electron mobilities were measured by a Hall effect and a magnetoresistant effect at low temperatures down to 0.4 K. Pronounced Shubnikov-de Haas (SdH) oscillations were observed at a low temperature showing two dimensional electron gases (2 DEG) in a tensile strained Si quantum well. The electron sheet density ($n_{s}$) of 1.5${\times}$$10^{12}$[$cm^{-2}$] and corresponding electron mobility of 14200 [$cm^2$$V^{-1}$$s^{-1}$] were obtained at low temperature of 0.4 K from Si/$Si_{1-x}Ge_{x}$ MOD quantum well structure with thermally grown oxide.

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