= Substitutional semiconductor doping
<Substitutional semiconductor doping> replaces selected host atoms with impurity atoms on ordinary lattice sites. A shallow <donor impurity> can supply a mobile conduction electron and remain positively charged; a shallow <acceptor impurity> can capture an electron and leave a mobile valence hole, remaining negatively charged. In nondegenerate, substantially ionized material, donor-dominated doping raises the <chemical potential> toward the conduction edge and acceptor-dominated doping lowers it toward the valence edge. Dopants do not create net bulk charge in a neutral sample: fixed impurity charge compensates the mobile carrier charge. Freeze-out, compensation and degeneracy qualify the simplest relation between dopant and carrier densities.
Back to article page
