The Fermi energy of a doped semiconductor is different from that of a pure semiconductor. Consider silicon, where the energy difference between the top of the valence band and the bottom of the conduction band is 1.11 eV. At a temperature of 300 K the Fermi energy of pure silicon lies approximately between the bottom of the conduction band and the top of the valence band. (a) Calculate the probability of occupying a state at the bottom of the conduction band. Consider now that the silicon has been doped with donor atoms that introduce a state at 0.15 eV below the conduction band background. Doping also caused the Fermi level to be shifted to an energy 0.11 eV below the bottom of the conduction band. (b) Under these conditions, calculate the occupancy of the lower end of the conduction band. (c) Calculate the probability that the level introduced by the donor impurities is occupied.
The Fermi energy of a doped semiconductor is different from that of a pure semiconductor. Consider silicon, where the energy difference between the top of the valence band and the bottom of the
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