When a pentavalent impurity is added to a pure semiconductor, it becomes
Answer Details
In a pure semiconductor, all atoms in the crystal lattice are identical, and the conductivity of the material is low. When a small amount of impurity atoms are added to the pure semiconductor, it is called doping, and it significantly changes the conductivity of the material. When a pentavalent impurity, such as antimony or arsenic, is added to a pure semiconductor, it is called n-type doping. The added impurity atom has an extra electron that is weakly bound to the atom, and it is easily excited by thermal energy to jump into the conduction band of the semiconductor. This creates an excess of free electrons in the material, which increases its conductivity. Therefore, the answer is: an n-type semiconductor.