explain the solution

Problem 3. An intrinsic Si sample is doped with donors from one side such that Ny=Noexp( ( ), where No = 1015cm-3 and 1 = 100 um. Here we assume that the doping profile can be considered as gradual variation and the semiconductor region is quasi-neutral. (a) Calculate the built-in electric field E(x) at 300K in equilibrium over the range for which Na n. Note KT/q = 0.026 V at 300K. A: Since Na ni and the doping is gradual variation, we have n Ne = Noexp(, ) Then the built-in electric field is 1 dE kT 1 dn kT 0.026V E(x) = = 2. 6V/cm q da q ndx 100 jer