Impurity level
= Impurity level
An <impurity level> is an electronic <energy level> associated with a dopant or defect in a <semiconductor>. A shallow <donor impurity> introduces a level just below the <conduction band>, and a shallow <acceptor impurity> introduces one just above the <valence band>. Under electrostatic <band bending>, these levels shift with the local band edges in the same material; their occupation is determined relative to the equilibrium <chemical potential>.