Condensed Matter - Semiconductor

In an n-type semiconductor, which of the following is true of impurity atoms?

1. They accept electrons from the filled valence band into empty energy levels just above the valence band.
2. They accept electrons from the filled valence band into empty energy levels just below the valence band.
3. They accept electrons from the conduction band into empty energy levels just below the conduction band.
4. They donate electrons to the filled valence band from donor levels just above the valence band.
5. They donate electrons to the conduction band from filled donor levels just below the conduction band.

(GR9677 #78)

Solution:

Semiconductor:

n-type:

• n for negative-charge
• atoms have extra electron
• donors to the conduction band

p-type:

• p for positive-charge (holes)
• atoms have missing electrons
• acceptors in the valence band

Source: physics.udel.edu

Answer: E