EE569 IPC Practice Test 2025 – Comprehensive Exam Prep

N-type semiconductors are characterized by having excess electrons, which play a crucial role in their electrical conductivity. In N-type materials, typically made by doping a pure semiconductor like silicon with elements that have five valence electrons (such as phosphorus or arsenic), the additional electrons from the dopant atoms become free to move throughout the crystal lattice. This results in an increase in the number of negatively charged carriers (electrons), which improves the semiconductor's ability to conduct electrical current.

The presence of these extra electrons facilitates conduction by allowing them to move more freely in response to an electric field. As a result, N-type semiconductors are primarily utilized in various electronic components, such as diodes and transistors, because they can effectively manage the flow of electrical charge.

The other choices describe characteristics that do not apply to N-type semiconductors. For example, excess protons would relate to positively charged carriers (holes) found in P-type semiconductors, while stating that they contain no charged carriers contradicts their inherent property of hosting free electrons as charge carriers. Lastly, while thermal energy does influence semiconductor conductivity in general, it is not a defining characteristic specific to N-type semiconductors like the excess of electrons is.