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10
CH1012
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-
