Maker Pro
Maker Pro

PN Junction



Jan 1, 1970
Hi All,

I have a question on the currents in the PN Junction diode. This has
been bugging me for a lot of time.

When the PN junction is forward biased, how does the holes from the
P-type move into the N-type ?

Since for the fomation of hole in the N-type, a valency electron should
occupy the hole near the junction of P-type. But there are free
electrons in P-type, which can occupy the holes near junction of
P-type, considering the fact that their mobility is higher when
compared with holes.
Will the valence electrons in N-type has any chance to occupy the holes
of P-type, overcoming the speed of free electrons ?

Also when a hole is formed near the junction of N-type, dont you think
there is a chance of free electron of n-type taking the placeof that

Please answer my question as soon as possible.



Jan 1, 1970
You should probably find a good book on Micro Electronic Circuits that
explains this.

Basically, when you forward bias the PN junction you narrow the
depletion region. Once this happens, the application of voltage
(pressure) can cause carries to pass through.