What type of doping produces n-type materials?

N-type materials are formed through donor doping, which involves introducing impurities into a semiconductor that have more valence electrons than the semiconductor itself. In silicon, for instance, which has four valence electrons, donor impurities such as phosphorus (which has five valence electrons) are added. This extra electron from the donor atoms becomes free to move, significantly enhancing the conductivity of the material by increasing the number of charge carriers, which are negative electrons in this case.

This process effectively shifts the electronic balance towards negative charge carriers, hence the designation of 'n-type' (where "n" stands for negative). The introduction of the donor atoms provides additional electrons that are not tied up in covalent bonds between silicon atoms, allowing for increased electrical conduction.

Other types of doping, such as acceptor doping, would introduce elements that accept electrons, thus creating holes (positive charge carriers) and leading to p-type materials, rather than enhancing electron availability. Regular and valence doping are not standard terms used to categorize doping types in semiconductor physics and do not accurately describe the mechanism that leads to the formation of n-type materials.