1. The problem statement, all variables and given/known data Show that for N-type material the carrier concentration is roughly the donor atom concentration. Explain why a N-type material is conducting at much lower temperature then a intrinsic semiconductor 2. Relevant equations maybe no equations are needed here 3. The attempt at a solution The number of carriers in the conduction and valence band with no externally applied bias is called the equilibrium carrier concentration. For majority carriers, the equilibrium carrier concentration is equal to the intrinsic carrier concentration plus the number of free carriers added by doping the semiconductor. Under most conditions, the doping of the semiconductor is several orders of magnitude greater than the intrinsic carrier concentration, such that the number of majority carriers is approximately equal to the doping.