As we have seen majority carriers (electrons in n-type material holes in p-type) are the main players in a conventional semiconductor diode By initial diffusion across the p-n junction they set up a depletion layer and create a potential barrier Forward-biasing the diode reduces the height of the barrier marking it easier for them to cross the junction and produce substantial current in reverse bias the barrier increases and current flow is severely inhibited Diode action is principally due to the behaviour of majority carriers under the influence of an applied external voltage