What defines n-type semiconductors?

N-type semiconductors are specifically defined by the introduction of donor impurities, which provide additional electrons that serve as the primary charge carriers. When certain materials, typically from Group V of the periodic table, such as phosphorus or arsenic, are added to a pure semiconductor like silicon (which is from Group IV), they donate extra electrons to the system. This process enhances the conductivity of the semiconductor because these extra electrons can move freely, allowing current to flow more easily.

The role of donor impurities is crucial because they create an abundance of negatively charged carriers (electrons) compared to the native holes that exist in the semiconductor. As a result, the term "n-type" reflects the fact that the majority carriers in this material type are negatively charged electrons. This characteristic distinguishes n-type semiconductors from p-type semiconductors, which have an abundance of positive charge carriers (holes) and are created by the introduction of acceptor impurities.