Graphene

1
Graphene

• Boris Torres
• MEEN 3344
• Material Science

2
Graphene

• Graphene is a one-atom-thick planar sheet of
  carbon atoms that are densely packed in a
  honeycomb crystal lattice.
• Graphite itself consists of many graphene sheets
  stacked together.
• The carbon-carbon bond length in graphene is
  approximately 0.142 nm.

3
Graphene production

• Graphene sheets in solid form (e.g. density gt
  1g/cc) is presently one of the most expensive
  materials on Earth.
• Researchers obtained relatively large graphene
  sheets (eventually, up to 100 micrometers in size
  and visible through a magnifying glass) by
  mechanical exfoliation (repeated peeling) of 3D
  graphite crystals.
• Another method is to heat silicon carbide to high
  temperatures (1100C) to reduce it to graphene.

4
Properties of Graphene

• The resistivity of the graphene sheet is 10-6
  Ocm, less than the resistivity of silver, the
  lowest resistivity substance known at room
  temperature.
• Graphene is the strongest substance known to man.
  Its Young's modulus is 0.5 TPa, which differs
  from bulk graphite.
• These intrinsic properties could lead to the
  possibility of utilizing Graphene for NEM systems
  applications such as pressure sensors, and
  resonators.

5
Properties of Graphene

• Engineering professors at Columbia University
  tested graphene's strength at an atomic level by
  indenting a perfect sample of the material with a
  sharp probe made of diamond.
• Electrons move through graphene with almost no
  resistance, generating little heat. What's more,
  graphene is itself a good thermal conductor,
  allowing heat to dissipate quickly.

6
Graphene and Applications

• By oxidizing graphene flakes, and then floating
  them in water, the graphene flakes form a single
  sheet and bond very powerfully called Graphene
  oxide paper.
• Applications
• Membranes with controlled permeability
• Supercapacitors for energy applications.
• Graphene electronics could be useful for
  communications and imaging technologies that
  require ultrafast transistors.

7
References

• Graphene http//en.wikipedia.org/wiki/Grapheneacce
  ssed on March, 29 2009
• Graphene Confirmed the Worlds Stronged Known
  Material http//gizmodo.com/5026404/graphene-confi
  rmed-as-the-worlds-strongest-known-material
  accessed on March, 29 2009
• Nanotechnology Reserchers go Ballistic Over
  Graphene http//www.nanowerk.com/spotlight/spotid
  2340.php accessed on March 29, 2009
• TR10 Graphene Transistors http//www.technologyre
  view.com/read_article.aspx?chspecialsectionssce
  merging08id20242 accessed on March 29, 2009
• Graphene Charged Up http//www.natureasia.com/asi
  a-materials/highlight.php?id77 accessed on March
  29, 2009