WAEC Physics 2022 Paper

Concept:Doping is the process of adding impurity atoms to an intrinsic semiconductor to change its electrical properties.A p-type semiconductor is formed when the dopant atoms create extra positive charge carriers called holes.Explanation:When an acceptor element is added to an intrinsic semiconductor, it has only three valence electrons.This creates a deficiency of electrons, leaving behind holes in the crystal structure.Holes act as the majority charge carriers in the resulting semiconductor.Since holes are positively charged, the material becomes a p-type semiconductor.In contrast, adding a donor element produces an n-type semiconductor with electrons as the majority carriers.Therefore, to obtain a p-type semiconductor, an acceptor element must be added during doping.Answer:C. An acceptor element is added.