A semiconductor is said to be doped when it has added to it small quantities of:

Doping is the manufacturing process of intentionally introducing specific, controlled amounts of foreign atoms into a pure semiconductor lattice. In materials science and electronics, these foreign atoms are formally referred to as "impurities." Depending on the type of impurity added (such as antimony or boron), the silicon becomes either N-type or P-type. While the end result of doping is a change in the number of available charge carriers like electrons, the physical elements added to the crystal are always termed impurities.