Introduction of hole semiconductor
Hole-type semiconductors, also known as P-type semiconductors, are semiconductors with positively charged hole conduction. A small amount of trivalent element indium or aluminum is doped into pure silicon. Because there are three valence electrons around the indium or aluminum atom, it lacks one electron when forming a covalent bond with the surrounding 4-valent silicon atom to form a hole. Holes are equivalent to positively charged particles and play a major role in the conduction of such semiconductors.