Question 4
(a) What is an intrinsic semiconductor?
(b) Distinguish between the p-type and n-type semiconductors.
Observation
A good percentage of the candidates provided the correct response. However, some candidates misfired as they gave textbooks description and theories of semiconductors without hitting the bull’s eye.
The expected answer
(a) Intrinsic semiconductor contains equal number of free electrons and holes
(b)
p-type |
n-type |
Has holes as the majority carriers of electricity |
Has electrons as the majority carriers of electricity |
Impurity is trivalent |
Impurity is pentavalent |
Created by an acceptor impurity |
Created by donor impurity |
Carries a net positive charge |
Carries a net negative charge |