forward bias (applying a positive voltage to the p-side with respect to the n-side) narrows the depletion region and lowers the barrier to carrier injection (shown in the figure to the right). in more detail, majority carriers get some energy from the bias field, enabling them to go into the region and neutralize opposite charges. the more bias the more neutralization (or screening of ions in the region) occurs. the carriers can be recombined to the ions but thermal energy immediately makes recombined carriers transition back as fermi energy is in proximity. when bias is strong enough that the depletion region becomes very thin, the diffusion component of the current (through the junction interface) greatly increases and the drift component decreases. in this case, the net current flows from the p-side to the n-side. the carrier density is large (it varies exponentially with the applied bias voltage), making the junction conductive and allowing a large forward current. the mathematical description of the current is provided by the shockley diode equation. the low current conducted under reverse bias and the large current under forward bias is an example of rectification.