1- Element semiconductors are located in the fourth column of the periodic table of elements, what does make these elements different from other elements?
2- What is the difference between valence electrons in an atom with other electrons?
3- What is the difference between conducting material, semiconductors, and insulators based on their bandgap energy?
4- Compare the bandgap energy between Si and Ge. Why Si has a larger bandgap energy?
5- What is the definition of unit cell in a lattice?
6- What is the difference between a direct bandgap semiconductor and an indirect bandgap semiconductor and provide a few example for each.
7- An orange light emitting diode emits green light in low temperatures, why?
8- What is Fermi Distribution and how does it change with temperature?
9- What are Nc and Nv? And what do they show?
10- What is polysilicon?
11- What is complete ionization? How much energy is required to ionize "B" and "As" in Silicon?
12- Explain what happens when n-type impurities are added to Si.
13- What is the difference between intrinsic and extrinsic semiconductors?
14- Explain the following Figure:
15- Explain the following Figure:
16- In a diamond crystal, the lattice constant, a, is 0.356 nm, what is its atomic density (number of atoms per cm-3)?
17- In a diamond crystal, the lattice constant is 0.356 nm, what is the minimum distance between the atoms?
18- Find the density of electrons and holes in Si if the density of n-type impurity is 1.5ni and the density of p-type impurity is 1.2ni, where ni is the intrinsic density of carriers in Si at T=500K (Hint use Fig. 1.18).
19- Is the semiconductor in question 18 a degenerate semiconductor or a non-degenerate semiconductor?
20- Show eV is an energy unit.
Do you have any suggestion for improving the instructor's teaching style?
Answers are supposed to be short and should not exceed two lines per question.