- #1
rire1979
- 2
- 0
Upon some calculation I arrive to the expression:
d2DPn(x)/dx2 = DPn(x)/Lh2
Where:
DPn(x) = Pn(x) + Pno - excess minority carriers (holes) concentration in the n-type part of the pn junction.
Now the roots to the characteristic equation are +/- 1/Lh where Lh is the length of the diffusion.
Therefore the solution looks like:
DPn(x) = Ae-1/Lh + Be1/Lh
I know for a fact the solution is DPn(x) = DPn(0)e-x/Lh
The initial conditions would be that:
@ x = 0 we have hole concentration DPn(0)
@ x = Lh we have DPn(Lh) = 0
But I have no idea how to arrive at the solution in bold. I'm missing something and I was thinking you could help.
Thank you.
d2DPn(x)/dx2 = DPn(x)/Lh2
Where:
DPn(x) = Pn(x) + Pno - excess minority carriers (holes) concentration in the n-type part of the pn junction.
Now the roots to the characteristic equation are +/- 1/Lh where Lh is the length of the diffusion.
Therefore the solution looks like:
DPn(x) = Ae-1/Lh + Be1/Lh
I know for a fact the solution is DPn(x) = DPn(0)e-x/Lh
The initial conditions would be that:
@ x = 0 we have hole concentration DPn(0)
@ x = Lh we have DPn(Lh) = 0
But I have no idea how to arrive at the solution in bold. I'm missing something and I was thinking you could help.
Thank you.