Q. Explain the compositional defects.

Ans. Compositional Defect: This defect due to

(a)    Alloying an element to original crystal.

(b)   Impuring atom during original crystallization.

These defects are responsible for functioning of most semiconductor devices.

A substitutional impurity defect is also a point defect in which a foreign atoms that substitutes for a parent atom in the crystal lattice e.g. in bras, zinc is a substitutional atom in the copper.

A interstitial impurity is a small sized atom occupying space between the regularity positioned atoms.