-Make sure you can draw the bandgaps for semiconductors and metals.
-Where is the Fermi energy in a metal? an intrinsic semiconductor? an n-type semiconductor? a p-type semiconductor?
-Make sure you understand doping in a semiconductor. What is added to make it n-type? for p-type?
-A lot of calculations were done in the last section. Make sure you can calculate EF, NC, NV, ni, n, and p for intrinsic, n-type, and p-type semiconductors!!
-Sketch out g(E) and f(E) as a function of energy. Combine them to get n(E). What does your profile look like? After you sketch it, compare it with Figure 4.27.
-Plot how electron density as a function of temperature changes for an n-type semiconductor.
-*(Apply your knowledge) Plot how the hole concentration changes as a function of temperature for an n-type semiconductor.
-What is the saturation temperature?
-*(Apply your knowledge) How would the saturation temperature change if you increased the dopant concentration? if you decreased the band gap?
-What variables in Eq. 5.21 and 5.22 are temperature dependent? (In other words, where does the temperature dependency of mobility come from?)
-How does the impurity concentration affect mobility?
-Study Figure 5.18. In what regimes is impurity scattering dominating and in what regimes is thermal scattering dominating?
-Why in Fig. 5.19 is the drift mobility for holes less than that of electrons?
-Plot conductivity as a function of temperature for an n-type semiconductor. Explain the hump in the middle- why does conductivity start to increase and then decreases?
-*Apply your knowledge: How would conductivity plot look for a p-type semiconductor?
-Review: how did conductivity as a function of temperature look for a metal?
-*Apply your knowledge: Think of the use of a computer chip which has metal interconnect lines and semiconductor channels (paths) the electrons travel along. How will increasing temperature (the chip heats up during use), affect the current (electrons/second) in the metal and the semiconductor?
-What are the definitions of degenerate and non-degenerate semiconductors?
-What statistical model do you need to apply to the degenerate case? How about the non-degenerate case?
Important terms you should know
-saturation temperature
-intrinsic temperature
-ionization, intrinsic, and extrinsic ranges
-mass action law
-electrical neutrality condition
-degenerate
Go to the textbook website and check out these solved problems (in the "Solved Problems" section.