1-3-1. Forward biasing

In forward bias, the p-type side is more positively biased than the n-type side. When a pn junction diode is forward-biased at V_F, most of it is applied across the pn junction, causing the diffusion potential to decrease by V_F. As a result, electrons, the majority carriers in the n-type semiconductor, diffuse from a region with a higher carrier density. (Similarly, holes, the majority carriers in the p-type semiconductor, diffuse from a region with a higher carrier density.) Electrons are injected into the n-type semiconductors from the bias to compensate for the amount of electrons reduced by diffusion whereas holes are injected into (i.e., electrons are drawn away from) the p-type semiconductor. As a result, current continues flowing.