When does intrinsic semiconductor become an extrinsic semiconductor? Illustrate.

Semiconductor doping is the process which changes an intrinsic semiconductor to an extrinsic semiconductor. During doping, impurity atoms are introduced to an intrinsic semiconductor. Impurity atoms are atoms of a different element than atoms of the intrinsic semiconductor. Impurity atoms act as either acceptors or donors to the intrinsic semiconductor, changing electron and hole concentrations of the semiconductor.