Si is an important semiconductor. At room temperature, i.e., 298K, its energy gap Eg is 1.107 eV, the electron (ue) and hole (un) mobility is 0.14 and 0.038 m?/V s, respectively. The carrier density is 1.4 x1016 m3. (12 points) (a) Calculate the conductivity of Si at room temperature. (b) Calculate its Fermi level (EF). (c) Calculate its conductivity at 100C. (d) In order to improve its conductivity, the Si is doped with a small amount of Al. Please briefly explain the mechanism of conductivity improvement by doing with Al. (e) The doping with Al shifts down the Erby 0.2 eV. Assuming the acceptor level (Ea) of the doped Si in (d) is 0.1 eV, illustrate the position of EF, Ea, and Eg in the energy band structure below: Conduction band Valence band