About: Carrier scattering

Defect types include atom vacancies, adatoms, steps, and kinks that occur most frequently at surfaces due to the finite material size causing crystal discontinuity. What all types of defects have in common, whether surface or bulk defects, is that they produce dangling bonds that have specific electron energy levels different from those of the bulk. This difference occurs because these states cannot be described with periodic Bloch waves due to the change in electron potential energy caused by the missing ion cores just outside the surface. Hence, these are localized states that require separate solutions to the Schrödinger equation so that electron energies can be properly described. The break in periodicity results in a decrease in conductivity due to defect scattering.