Calculate the storage delay in a linearly graded p-n junction with the plot of

the doping profile shown below.

Attemp at solution:

I was given a hint that there would be electric field present.

Set up Continuity equation

due to symmetry , I could just do the p part then times by 2

I am assuming that E could be found by using poisson equation?

I am stuck on where to go from here, help is appreciated