Crystal Growth of III/V Semiconductor Nanowires

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Crystal Growth of III/V Semiconductor Nanowires

• Kobi Greenberg

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Metal organic molecular beam epitaxy (MOMBE)
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Future applications of nanowires
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The vapor liquid solid growth mechanism
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TEM pictures of InP nanowires grown in our lab by
the vapor liquid solid method
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Two ways to arrange cannon balls
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Stacking fault formation
Wurzite nanowire With stacking fault
Zincblende nanowire
Wurzite nanowire
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Limitations of the vapor liquid solid method

• Difficult to eliminate stacking fault
• Very sensitive to wafer surface effects
  Calahorra, Greenberg et al. nanotechnology 2012

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The selective area vapor liquid solid growth
method
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TEM pictures of InP nanowires grown in our lab by
selective area vapor liquid solid method no
stacking faults
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Advantages of the selective area vapor liquid
solid method

• Easy to eliminate stacking fault in InP nanowires
• not sensitive to wafer surface effects
• Predictable growth rate

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Fabrication
Wafer cleaning
Si3N4 deposition
Electron sensitive resist coating
Electron beam lithography development BOE
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nanowire heterostuctures important for device
applications

• conventional layers of materials having different
  lattice constant cannot be grown on top of each
  other as single crystals.
• Due to their small dimensions, a stack of
  materials with different lattice constants can be
  grown as a single crystal

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Heterostructure analysis by EDX and STEM HAADF
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Summary

• Selective area vapor liquid solid is the method
  of choice for defect free nanowire growth.
• Heterostructures of InP and GaP having 7.7
  lattice mismatch were demonstrated.
• Method will be implemented for other materials
  such as GaAs, GaP,InAs and their heterostuctures.

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