Correct Answer: Extrinsic semiconducter

Solution : The correct option is Extrinsic semiconductor.

When arsenic atoms are introduced into the germanium lattice, it transforms into an extrinsic semiconductor. Arsenic is a pentavalent impurity , with five valence electrons. When an arsenic atom is introduced into a germanium lattice, it forms four covalent connections with the germanium atoms while retaining one additional electron. This electron is weakly bonded to the arsenic atom and is quickly liberated by heat energy, resulting in a free electron. Because of the presence of free electrons in the germanium lattice, it is a better electrical conductor than pure germanium. Because of this, arsenic-doped germanium is referred to be an n-type semiconductor.