2.6. (a) Silicon is uniformly doped with 1022 phosphorus atoms/m'. As- suming that all these donor impurities are ionized, estimate the concentration of electrons and holes in this material under thermal equilibrium at 300 K. Hence, calculate the energy of the Fermi level in this material below the conduction-band edge. (b) Given that the donor level for phosphorus lies 0.045 eV below the conduction-band edge, calculate the probability that this level is occupied by an electron and hence check on the assumption that all donors are ionized. (Use NC - 3 X 1025 m), Ny = 1025 m3, and n = 1.5 X 1016 m?) 9