VE320 Intro to Semiconductor Devices Summer 2024 – Problem Set 2

Java Python VE320 Intro to Semiconductor Devices

Summer 2024 – Problem Set 2

Due: 11:59pm, June 7th

1. (a) Determine the total number (#/cm3) of energy states in silicon between EC and EC + 2kT at (i) T = 300K and (ii) T = 400K. (b) Repeat part (a) for GaAs.

2. (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 Ge.

3. Consider the energy levels shown in Figure 1. Let T = 300K. (a) If E1 – EF  = 0.20eV,

determine the probability that an energy state at E = E1  is occupied by an electron and the

probability that an energy state at E = E2  is empty. (b) Repeat part (a) if EF – E2  = 0.40 eV.

Figure 1. Energy levels for problem 3

4. (a) The carrier effective masses in a semiconductor are& VE320 Intro to Semiconductor Devices Summer 2024 – Problem Set 2 nbsp;mn * = 1.21m0  and mp * = 0.70m0.

Determine the position of the intrinsic Fermi level with respect to the center of the bandgap at T = 300K. (b) Repeat part (a) ifmn * = 0.80m0  and mp * = 0.75m0.

5. Semiconductor A has a band gap of 1 eV, while semiconductor B has a band gap of 2 eV. What is the ratio of the intrinsic carrier concentrations in the two materials (niA/niB) at 300 K. Assume any differences in the carrier effective masses maybe neglected.

6. The value p0  in Silicon at T = 300K is 2× 1016cm-3. (a) Determine EF – Ev. (b) Calculate the value of EC – EF. (c) What is the value of n0? (d) Determine EFi – EF.

7. The electron concentration in silicon at T = 300K is  n0  = 2 × 105cm −3 . (a) Determine the position of the Fermi level with respect to the valence band energy level. (b) Determine p0