A silicon semiconductor has its Fermi energy at 10kT below the center of the bandgap. Assume T = 300K, 10 3 1.5 10 i n x cm − = , kT = 0.026eV, Eg = 1.12eV. a) (5 points) Is the semiconductor n-type or p-type and why? 

b) Determine 0 0 n and p and impurity density and type (assume there is only one type of impurity) 

c)  What type and concentration of impurities need to be added to move the Fermi energy to 9kT above the center of the band