# Homework Help: SemiConductor Question

1. Feb 7, 2010

### th3bl0b

1. The problem statement, all variables and given/known data

Q1
A Si sample is doped with 10^16 per cm^-3 boron atoms and a certain
number of shallow donors. The fermi level (Ef) is 0.36 eV above Ei
(intrinsic energy level) at 300K. What is the donor concentration Nd?

For Si at 300K ni(intrinsic carrier concentration) = 1.5 x 10^10 per
cm cube

Q2
A Si sample contains 10^16 per cm^-3 In(indium) acceptor atoms and
a certain number of shallow donors. The In (indium) acceptor level is
0.16 eV above Ev(Valence band edge), and Ef is 0.26eV above Ev at
300K. How many in atoms in cm per cube are unionized (i.e. neutral)?

For Si at 300K ni(intrinsic carrier concentration) = 1.5 x 10^10 per
cm cube

2. Relevant equations

n(o) x p(o) = ni^2

n(o) = ni x e((Ef-Ei))/KT)

p(o) = ni x e((Ei-Ef)/KT)

3. The attempt at a solution

I haven't been able to make a good decision on how to start...

If you have any suggestions, let me know. I'm open to everything!

Thanks