Substitutional dopants (impurities that replace atoms in the crystal lattice) are used to modify the electrical properties of semiconductors. (8 pts total)
(a) Name a specific element that is commonly used as an n-type dopant in Si and write the general name that describes this type of dopant. (4 pts)
(b) In order to contribute a delocalized charge carrier to the semiconductor, a dopant must ionize. When the dopant you chose in part (a) ionizes, what type of charge carrier is contributed and what is the charge state of the ionized dopant left behind in the lattice? (4 pts)