It is often more convenient to express Equation 3-92 in terms of the carrier concentrations rather than the relevant quasi-Fermi levels. From
Equation 3-49:
where ΔEd=
Ec-
Ed and
ΔEa=
Ea-
Ev.
Equation 3-94 is used in COMSOL Multiphysics when incomplete ionization with the standard ionization model is chosen in the Dopant Ionization section of the
Semiconductor Material Model node. It is also possible to select a user defined ionization model, in which case the ionization ratios are specified directly by user-defined expressions. If complete ionization is chosen (the default) then
Nd+=Nd and
Na–=Na.