Tunneling Phenomena in NanoParticle Composites

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Tunneling Phenomena in Nano-Particle Composites

• REU Intern Alex Di Sciullo Jones
• Mentor Dr. Adam Huang
• Graduate Student Feng Pan

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Background

• As nano-sized particles of either metal or carbon
  (conductors) are added to elastomer (insulator),
  the composite becomes more conductive

Carbon Black
Elastomer
Images taken by AFM in Dr. Huangs lab
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Background ctd.

• Particles arent touching yet a current passes
  through the material (hasnt reached percolation
  threshold yet)
• Past tunneling has been used to explain this
• Electron jumps from particle to particle across
  composite

insulator
conductor
Current

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Reason Behind Experimentation

• Problem tunneling is not thought to exist in
  particles beyond around 10nm apart
• At concentrations under 35, spacing can be much
  larger and yet material is still conductive
• New Question if tunneling is not
• responsible, then what is?

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To Make Progress

• See what actually occurs in electric field
  between particles
• Observe how polarization of particles effects how
  current passes through
• See how change in particle concentration and
  electric field has effects

insulator
conductor


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Current

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Skills and Equipment

• Become familiar with use of AFM (atomic force
  microscope)
• Research and purchase probe, head, and software
  for AFM to produce image of electric field
  topography of sample
• Produce samples to be tested with carbon black
  and elastomer at different concentrations
• Finally testing with current passing through
  sample, from which conclusions can be made

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Why Carbon Black?

• In the past, tests done on carbon nanotubes
• Cylindrical shape, different aspect ratio
• Carbon Black
• Treat as spheres
• Distance between particles in
• concentration more easily controlled
• better results for conclusions

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To Close

• Thank you for your time and Im glad to answer
  any questions you might have.