# Drift velocity in P-N Junctions

• I
When a P-N junction is in reverse bias, the drift velocity of the system increases, so why is there no current flow? Is the drift velocity not connected to the current?

When a P-N junction is in reverse bias, the drift velocity of the system increases, so why is there no current flow? Is the drift velocity not connected to the current?

pl. explain how the drift velocity increases in a biased p-n junction.
moreover Is the current dependent on drift velocity if a voltage is applied?

pl. explain how the drift velocity increases in a biased p-n junction.
moreover Is the current dependent on drift velocity if a voltage is applied?
In the depletion zone (when in reverse bias) there is a steeper potential gradient and so the drift current increases?

I thought the current was dependent on the drift velocity

• drvrm
Henryk
Gold Member
When a P-N junction is in reverse bias, the drift velocity of the system increases, so why is there no current flow?
Actually, there is a current flowing. It is called reverse current and it is only weakly dependent on the reverse voltage.
The field in the depletion region of a p-n junction is quite strong and if you reverse bias the junction, any charge carrier within that region will be swept out immediately. Therefore, the reverse current depends on rate of carrier generation within the depletion region.