- #1

rire1979

- 2

- 0

d

^{2}DPn(x)/dx

^{2}= DPn(x)/Lh

^{2}

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}+ Be

^{1/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.