A silicon sample of length L is uniformly doped with N = 10^14 cm^-3 acceptors. We shine laser light on one end of this sample that produces p-n = 10^14 cm^-3 electron-hole pairs (EHP) only at that edge. A contact at the other end x = L extracts all excess carriers, i.e., p-nx = 0. Minority carrier lifetime of electrons is 1 sec, and that of holes is 0.1 usec.
Assume that L << Ln, Lp, i.e., the p-n terms in the diffusion equation can be neglected.
Find Op(x) = On(x) for this case. Hint: You just need to integrate.
Find the diffusion current density J(x) for this case as a function of x, and find its value at x=0, x=L/2, and x=L, with L=0.1m.