1
PN Junction Information3 and 5 March 2014
Charge distribution in the depletion region Electric potential in the
depletion region
E-field in the depletion region
In the p-region
),( nx
d xxeN
E
In the n-region
)( px
a xxeN
E
ndpa xNxN
(due to charge neutrality or E-field continuity)
x
pa
x
ndxeNxeN
E
max
In the p-region
2)(2
1p
x
a xxeN
In the n-region
2
2
1)2(
2
1p
x
dn
x
d xeN
xxxeN
22
2
1pand
xbi xNxN
eV
2
Summary of PN Junction under Equilibrium Condition
22
2
1pand
x
bi xNxNe
V
2ln
i
dabi n
NNkTeV
ndpa xNxN
dad
abisn NNN
N
e
Vx
12
daa
dbisp NNN
N
e
Vx
12
da
dabispn NN
NN
e
VxxW
2
xp xnW
33
The PN Junction and Band Diagram
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