Extrinsic semiconductors: A Si crystal has been doped with phosphorus with a concentration of 10 ppm. The lattice constant of Si is 5.43 . (a) Are the phosphorus impurities donors or acceptors in the Si crystal? (b) What are the majority and minority carriers in this doped Si crystals? Find their corresponding concentrations. (c) Find the Fermi level location in this doped Si crystal. (d) Calculate the conductivity of the crystal. How does it compare with that of intrinsic Si or a Cu metal?