Germanium (Ge) is a Group 14 element and behaves as an intrinsic semiconductor. Antimony (Sb) is a Group 15 element, which means it is a pentavalent impurity. When a pentavalent impurity is added to an intrinsic semiconductor, it acts as a donor atom by providing extra free electrons for conduction. This forms an n-type semiconductor. In an n-type semiconductor, electrons are the majority charge carriers, meaning there will be more free electrons than holes. Additionally, adding impurities (doping) increases the conductivity and therefore decreases the resistance of the semiconductor.