Free Carrier Concentration
is the concentration
of free carriers
in a doped semiconductior
. It is similar to the carrier concentration in a metal and for the purposes of calculating currents or drift velocities can be used in the same way. It should be noted that free carriers are electrons (or holes
) which have been introduced directly into the conduction (valence
) band by doping and are not promoted thermally. For this reason electrons (holes) will not act as double carriers by leaving behind holes (electrons) in the other band.