ECE 874: Physical Electronics

1
ECE 874Physical Electronics

• Prof. Virginia Ayres
• Electrical Computer Engineering
• Michigan State University
• ayresv_at_msu.edu

2
Lecture 21, 12 Nov 12
3
f(E) probability Fermi distribution function
Streetman and Banerjee, Solid State Electronic
Devices (Pierret Section 4.2 and Pr. 4.8)
4
The Fermi (energy) level EF
50
5
At T 0K
6
f(E) at T above 0K
7
f(E) at T above 0K
8
DOS available statesVersus f(E) and EF
9
(No Transcript)
10
(No Transcript)
11
Approximation/limits on f(E)
Recall
Two conditions Temperature T E EF gt 0 E EF
lt 0
12
Restricting E to values for which there are
available states this is Two conditions Temper
ature T E EF gt 0, where E gt EC E EF lt 0,
where E lt EV
EC
Ei
EV
13
Two conditions gt Four conditions Temperature
T Degeneracy E EF gt 0 gt EF lt EC lt E versus
EC lt E lt EF
1. Non-degenerate n-type doping
2. Degenerate n-type doping
EF
EC
EC
EF
Ei
Ei
EV
EV
14
Four conditions Temperature T Degeneracy EF
E gt 0 gt E lt EC lt EV versus E lt EV lt EF
3. Non-degenerate p-type doping
4. Degenerate p-type doping
EC
EC
Ei
Ei
EF
EV
EV
EF
15
Approximation/limits on f(E)
16
Approximation/limits on f(E)
17
Approximation/limits on f(E)
Use the hot limit in ECE 874.
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)