§ 1.3 Semiconductor Materials4. In

§ 1.3 Semiconductor Materials
4. In your own words, define semiconductor, resistivity, bulk resistance, and ohmic contact resistance.
5. (a) Using Table 1.1, determine the resistance of a silicon sample having an area of 1 cm2 and a length of 3 cm.
(b) Repeat part (a) if the length is 1 cm and the area 4 cm2.
(c) Repeat part (a) if the length is 8 cm and the area 0.5 cm2.
(d) Repeat part (a) for copper and compare the results.
6. Sketch the atomic structure of copper and discuss why it is a good conductor and how its structure is different from germanium and silicon.
7. In your own words, define an intrinsic material, a negative temperature coefficient, and covalent bonding.
8. Consult your reference library and list three materials that have a negative temperature coefficient and three that have a positive temperature coefficient.
§ 1.4 Energy Levels
9. How much energy in joules is required to move a charge of 6 C through a difference in potential of 3 V?
10. If 48 eV of energy is required to move a charge through a potential difference of 12 V, determine the charge involved. 11. Consult your reference library and determine the level of Eg for GaP and ZnS, two semiconductor materials of practical value. In addition, determine the written name for each material.
§ 1.5 Extrinsic Materials—n- and p-Type
12. Describe the difference between n-type and p-type semiconductor materials.
13. Describe the difference between donor and acceptor impurities.
14. Describe the difference between majority and minority carriers.
15. Sketch the atomic structure of silicon and insert an impurity of arsenic as demonstrated for silicon in Fig. 1.9.
16. Repeat Problem 15 but insert an impurity of indium.
17. Consult your reference library and find another explanation of hole versus electron flow. Using both descriptions, describe in your own words the process of hole conduction.
§ 1.6 Semiconductor Diode
18. Describe in your own words the conditions established by forward- and reverse-bias conditions on a p-n junction diode and how the resulting current is affected.
19. Describe how you will remember the forward- and reverse-bias states of the p-n junction diode. That is, how you will remember which potential (positive or negative) is applied to which terminal? 20. Using Eq. (1.4), determine the diode current at 20°C for a silicon diode with Is 50 nA and an applied forward bias of 0.6 V.