Electrical Engineering ⇒ Topic : P-type Semiconductors

P-type Semiconductors

Trivalent atoms like indium, boron or gallium, all having three electrons in outer orbit, are added in small proportions to germanium. So three out of four possible covalent bonds will be formed.The fourth bond acts as a hole. A hole moves in a direction opposite to the direction of electron when potential difference is applied. This trivalent impurity is called P-type impurity. The majority carriers of charge in this type of semiconductor are holes so it is known as P-type semiconductor or P-type crystals.