(a) in pure silicon, the probability that a state at the bottom of the conduction band is occupied. (b) in doped silicon, the probability that a state at the bottom of the conduction band is occupied. (c) in doped material, the probability that a state (at the donor level) is occupied.

Question

Want to see the full answer?

Answer 1

Question

Chapter 41, Problem 37P

To determine

To calculate:

(a) in pure silicon, the probability that a state at the bottom of the conduction band is occupied.

(b) in doped silicon, the probability that a state at the bottom of the conduction band is occupied.

(c) in doped material, the probability that a state (at the donor level) is occupied.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

Doping changes the Fermi energy of a semiconductor. Consider silicon, with a gap of 1.11 eV between the top of the valence band and the bottom of the conduction band. At 300 K the Fermi level of the pure material is nearly at the midpoint of the gap. Suppose that silicon is doped with donor atoms, each of which has a state 0.10 eV below the bottom of the silicon conduction band, and suppose further that doping raises the Fermi level to 0.075 eV below the bottom of that band (see the figure below). For (a) pure and (b) doped silicon, calculate the probability that a state at the bottom of the silicon conduction band is occupied. (c) Calculate the probability that a donor state in the doped material is occupied. Conduction band Fermi Donor 1.11 eV level level Valence band

Time left In a phosphorous-doped (n-type) silicon, the Fermi level is shifted upward 0.1 eV. What is the probability of an electron's being thermally promoted to the conduction band in silicon (Eg = 1.107 eV at 25 deg C? Your answer must be to 2 significant figures or will be marked wrong. Ne

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. JUSTIFY ALL ANSWERS.