Raising potential of the p w.r.t n causes current to flow from p to n . Lowers potential barrier and diffusion dominates drift . Minority carriers injected into neutral region and diffuse toward plates. Recombine with majority carrier causing a net flow of current. Raising potential of the n w.r.t p causes current to flow from n to p .
Drift dominates diffusion .
For forward bias, the current is exponentially related to applied bias. The diffusion coefficients D p and D n represent the constant of proportionality . The concentration at the edge of the depletion region is an exponential function of the applied bias voltage. Repeating this analysis for p-region and summing the current contributions yields an expression for I D of an ideal diode. Otherwise, it is a long-base diode and the minority carriers have a chance to recombine with majority carriers.