CH1012
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10
p-TYPE SEMICONDUCTORS
p- type Semiconductors : positive
charge carriers.
• eg. Ga dopant atoms are added
to Si
Ga: has 3 valence e- Si: has 4 valence e-
Ga: has 3 valence e- Si: has 4 valence e-
•Each Ga adds an electron hole (+) to
the solid.
•A
new empty energy level called an acceptor band
forms at the top of the valence band
forms at the top of the valence band
•Si electrons are able to move into the
acceptor band leaving holes
in the valence band.
Again conductivity
increases but now
the charge carriers
are holes with a
positive charge.
in the valence band.
Again conductivity
increases but now
the charge carriers
are holes with a
positive charge.
e-
e-
