The electron concentration in a sample of uniformly doped n – type silicon at 3000 K varies linearly from 10^17/????^3 ???? ?? = 0 ???? 6 × 10^16/????^3 ???? ?? = 2????. Assume a situation that electrons are supplied to keep this concentration gradient constant with time. If electronic charge is 1.6 × 10^-19 coulomb and the diffusion constant ???? = 35 ????^2/??, the current density in the silicon, if no electric field is present is