Semiconductors

Semiconductors

  1. Semiconductor is a class of crystalline solid with conductivity between a conductor and an insulator.
  2. Example of semiconductors are:
    1. Silicon
    2. Germanium
    3. Boron
    4. Tellurium
    5. Selenium

The Silicon Crystal

  1. The typical example of semiconductor is silicon.
  2. Silicon has 4 valence electrons. Each of these 4 electrons are shared with another 4 silicon atoms to form 4 pairs of covalent bond, as shown in the diagram above.
  3. The bonded valence electrons are not free to move. Therefore silicon is not a good conductor at room temperature.
  4. At room temperature, a silicon crystal acts approximately like an insulator because only a few free electrons and holes are presence.