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For more information, please see full course syllabus of Chemistry
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Lecture Comments (2)

1 answer

Last reply by: Zachary McCoy
Sun Jan 5, 2014 4:36 PM

Post by Zachary McCoy on January 5, 2014

Note on P- and N-type semiconductors:
The partial charge on boron would be negative because it would draw in electrons from the Si atoms due to its higher electronegativity. Further, the formal charge on a boron atom bonded to four atoms is a formal negative charge (i.e. NOT positive).

Carbon Allotropes, Band Theory of Solids

  • Network solids are giant molecules

  • Difference between graphite – sheets of hexagons of C – and diamond – 3D tetrahedral network; properties related to structures

  • Novel carbon frameworks C-60 – buckyball; nanotubes

  • Conductivity varies metals >> semiconductors > insulators

  • In large crystals MOs combine to give bands; valence band; conduction band

  • Doping of insulator like Si with P gives n-type semiconductor

  • Doping of Si with Al gives p-type semiconductor

  • p/n junctions yield transistors and chips

  • Glasses: common ones made from quartz, sodium carbonate, calcium oxide; amorphous

Carbon Allotropes, Band Theory of Solids

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Diamond and Graphite 0:55
    • Diamond
    • Graphite
  • C-60: An Unexpected Allotrope 6:59
    • Buckyball (R. Buckminster Fuller)
  • Carbon Nanotubes 11:42
    • Possible Uses
  • Metals, Semiconductors, and Insulators 15:34
    • 3 Classes of Conductors
  • Conductivity and Band Theory 20:30
    • Example: Valence Band
  • P-Type and N-Type Semiconductors 27:21
    • Phosphorus to Silicon
    • Boron to Silicon
  • P/N Junctions 33:48
    • Integrated Circuit
  • Glasses and Ceramics 40:26
    • Glasses
    • Example: Common Window Glass
    • Ceramics