Chapter 1-4答案1

Chapter 1 (Odd)

1. Copper has 20 orbiting electrons with only one electron in the outermost shell. The fact that

the outermost shell with its 29

th

electron is incomplete (subshell can contain 2 electrons) and

distant from the nucleus reveals that this electron is loosely bound to its parent atom. The

application of an external electric field of the correct polarity can easily draw this loosely

bound electron from its atomic structure for conduction.

19

Q =

= 6.40  10



C

establish the covalent bonding. The majority carrier is the electron while the minority carrier

is the hole.

A p-type semiconductor material is formed by doping an intrinsic material with acceptor

atoms having an insufficient number of electrons in the valence shell to complete the covalent

bonding thereby creating a hole in the covalent structure. The majority carrier is the hole

while the minority carrier is the electron.

9. Majority carriers are those carriers of a material that far exceed the number of any other

carriers in the material.

Minority carriers are those carriers of a material that are less in number than any other carrier

of the material.

I

D

= I

s

= 50  10



9

(e

11.877

 1) = 7.197 mA

17. (a) T

K

= 20 + 273 = 293



6

(e





6

(1.07  10



6

0.1

I

D

= I

s

= 0.1



A

T = 40C: I

s



A) = 0.4

A

T = 50C: I

s



A) = 0.8

A

T = 60C: I

s



A) = 1.6

A

1.6



A: 0.1



21. From 1.19:

V

F

decreased with increase in temperature

1.7 V: 0.65 V  2.6:1

I

s

increased with increase in temperature

2



A: 0.1



A = 20:1

23. In the forward-bias region the 0 V drop across the diode at any level of current results in a

resistance level of zero ohms – the “on” state – conduction is established. In the reverse-bias

region the zero current level at any reverse-bias voltage assures a very high resistance level 

27. V

D

= 10 V, I

D

s

= 0.1



R

DC

= 100 M

As the reverse voltage increases, the reverse resistance increases directly (since the diode

leakage current remains constant).

29. I

D

= 10 mA, V

D

= 0.76 V

R

=

= 76 

r

d

=

= 3 

45. I

= 0.1 mA: r

 700 

The results support the fact that the dynamic or ac resistance decreases rapidly with

Chapter 1 (Even)

2. Intrinsic material: an intrinsic semiconductor is one that has been refined to be as pure as

physically possible. That is, one with the fewest possible number of impurities.

Negative temperature coefficient: materials with negative temperature coefficients have

decreasing resistance levels as the temperature increases.

10. Same basic appearance as Fig. 1.7 since arsenic also has 5 valence electrons (pentavalent).

12. 

14. For forward bias, the positive potential is applied to the p-type material and the negative

potential to the n-type material.

16. k = 11,600/n = 11,600/2 = 5800 (n = 2 for V

T

+ 273 = 100 + 273 = 373

18. (a)

(b) y = e

0

(c) For V = 0 V, e