Gold%20Quantum%20Wire

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Gold Quantum Wire

• Mina Fazlollahi
• 1382/3/10

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• Always more complex,
• Always smaller,
• are the main challenges of todays
• nanoelectronics.

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Topics of Discussion

• Synthesis
• Lithogrphy and MBE
• Template method with porous substrate
• Beaded nanowire
• Structure
• Atomic arrangement
• Multi-shelled wires
• Conductance
• Landauer Theory
• Mechanical Controllable Break Junction (MCB)
• Quantum point contacts (QPC)

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Synthesisgt lithography MBE

• Schematic picture of oblique evaporation of metal
  onto V-grooved InP(001) substrate

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Synthesisgt porous substrate

• a) Anodization

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Synthesisgt porous substrate

• b) pore filling , wire growth and template
  removal

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Synthesisgt porous substrate

• c) post treatment
• Before After

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Synthesisgt beaded nanowire

• Procedure ?

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structure

• Linear chain with single row of Au atoms
• Linear chain with double row (rectangular)
• A planar zigzag
• Etotal EEwaldEHartreeEExcEpEk

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Structuregt Atomic arrangement
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Structuregt multi-shelled wires

• Embededatom potential
• Etotal½?ij F ai- aj (rij) ?i Fai(?i)
• fcc(111) fcc(110)
  fcc(100)

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Conductancegt Landauer theory

• G
  (2e2/h) ?i Ti
• for ballistic transport Ti1 So G G0N
• G02e2/h Quantum of conductance
• N number of conduction channels

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Conductancegt MCB
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Conductancegt QPC

• Gold STM tip contact with gold island
• Conductance G It /Vb

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Conductancegt QPC

• Withdrawal of tip form gold island

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Possible application

• Interconnection in chips for ULSI
• STM tip
• Nanowire transistors
• Gas sensors
• Detection of diseases such as cancer
• Coming