diode property

we know that barrier potential of si diode=0.7 eV

when the same silicon diode is heavily doped ,does the barrier potential remains the same or not ??

No. You can have a tunnel diode (Tunnel diode - Wikipedia, the free encyclopedia).

Or a Schottky Diode
Schottky diode - Wikipedia, the free encyclopedia
It has the lowes barrier potential at around 0.2 to 0.3 volts
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OOPS! - That's a metal(gold)-semiconductor junction. The previous poster, crutschow, was correct that Tunnel Diodes are heavily doped.

Tunnel Diodes still need the normal forward voltage to start conducting, the voltage does go down afterwards though when the tunneling effect takes over.

Sceadwian said:

Tunnel Diodes still need the normal forward voltage to start conducting, the voltage does go down afterwards though when the tunneling effect takes over.

Click to expand...

Not quite correct. Tunnel diodes start conducting significantly at very low voltage. The volt-current curve goes through zero and is fairly linear up to the peak current (the start of the negative resistance region)which is typically in the low ma region at several 10's of mV. A normal diode only conducts in the µa region around the zero point.

It's only on the far side of the negative resistance region that they start to look like normal diodes.

Show's how much I pay attention to the curves =\