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Solid state question

  • Thread starter nhrock3
  • Start date
  • #1
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a silicon crystal is doped with 10^15 cm^-3 atoms of antimony
and its also doped with 10^16 cm^-3 atoms of boron

will the crystal be type p or type n

what will be the concentration of minory charge carriers and majority charge carriers
?

Boron has 3 electrons in outer circle
and Sb has 5 on the outer circle
so its type "p" because there there is more +3 then +5
thats as far as could go
how to find the concentration of minory charge carriers and majority charge carriers
 

Answers and Replies

  • #2
berkeman
Mentor
57,322
7,314
a silicon crystal is doped with 10^15 cm^-3 atoms of antimony
and its also doped with 10^16 cm^-3 atoms of boron

will the crystal be type p or type n

what will be the concentration of minory charge carriers and majority charge carriers
?

Boron has 3 electrons in outer circle
and Sb has 5 on the outer circle
so its type "p" because there there is more +3 then +5
thats as far as could go
how to find the concentration of minory charge carriers and majority charge carriers
But the two doping densities are not the same...
 
  • #3
5
0
boron is an acceptor donates 1 hole per atom.
Sb is a donor, donates 1 electon per atom

10^16 boron atoms vs 10^15 Sb means that this is a P type.

n0p0=ni^2

minority negative charge carriers : Npo=ni^2/p0 = 10^20/10^16 = 10^4 cm^-3

major charge carriers = 10^16
 
  • #4
415
0
what are n0 p0 and ni
?

what N represents in Npo=ni^2/p0 ?
 
  • #5
5
0
n0 is thermal equibrium density of electrons
p0 is thermal equilibruim density of holes

ni = electron density in intrinsic semiconductor

Npo is the thermal equilibrium minority carrier density.
 
  • #6
415
0
how you get that the "major charge carriers = 10^16 "
?
 

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