Final answer:
Doping is the process of introducing impurities into a semiconductor. Elements with one more or one fewer valence electron than silicon are commonly used as dopants. For example, adding an impurity like arsenic or aluminum to silicon can create n-type or p-type semiconductors, respectively.
Step-by-step explanation:
Doping is the process of deliberately introducing impurities into a semiconductor to change its properties. In the case of silicon, dopants with one more or one fewer valence electron are commonly used. Elements with the same number of valence electrons as silicon, such as germanium, are often used as dopants. For example, adding an impurity like arsenic, which has five valence electrons, to a silicon crystal creates an n-type semiconductor. Similarly, adding an impurity like aluminum, which has three valence electrons, creates a p-type semiconductor.