Description

1. (a) For silicon, find the ratio of the density of states in the conduction band at 𝐸=𝐸𝑐+𝑘𝑇 to the density of states in the valence band at 𝐸=𝐸𝑣−𝑘𝑇. (b) Repeat part (a) for GaAs.
2. (a) The Fermi energy in silicon is 0.30𝑒𝑉 below the conduction band energy 𝐸𝑐 at 𝑇=300𝐾. Plot the probability of a state being occupied by an electron in the conduction band over the range 𝐸𝑐≤𝐸≤𝐸𝑐+2𝑘𝑇. (b) The Fermi energy in silicon is 0.25𝑒𝑉 above the valence band energy 𝐸𝑣. Plot the probability of a state being empty by an electron in the valence band over the range 𝐸𝑣−2𝑘𝑇≤𝐸≤𝐸𝑣.
3. (a) Calculate the temperature at which there is a 10−8 probability that an energy state 0.60𝑒𝑉 above the Fermi energy level is occupied by an electron. (b) Repeat part (a) for a probability of 10−6.
4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.