= P-n junction
A <p-n junction> joins regions of a <semiconductor> with opposite majority <charge carriers>: <Electrons> on one side and <electron holes> on the other. It provides the junction modeled by the <Shockley diode equation>.
Near an unbiased <p-n junction>, <diffusion> leaves exposed ionized <donor impurities> and <acceptor impurities>. Their <electric field> opposes further majority-carrier transfer. At <thermal equilibrium>, drift and <diffusion> balance; there is no net <electric current>. <Forward bias> reduces the barrier to <carrier injection>; <reverse bias> enlarges it. A heavily doped <tunnel diode> adds a different transport route, <quantum tunnelling>, that the ordinary <Shockley diode equation> omits.
Back to article page
