A 5 μm long of p-type silicon has an acceptor dopingprofile given by
NA (x) = 10^14 + 10^18exp(-10^4x), where x is measuredin cm. Use Eq. to demonstrate that the material must have a nonzerointernal electric field E. What is the value of E at x=0 and x =5μm?
(Hint: In thermal equilibrium, the total electron and total holecurrents must be zero.)