Electronics projects - PN junction diode working animation

Click https://youtu.be/7HxG-XE4X3c for part 2 detailed explanation of PN-Junction diode.
Electronics projects - PN junction diode working animation
P-n junction diode is formed by joining semiconductor materials, Such as silicon.

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The atomic scale structure of silicon is shown here.
Impurity atom is added to the silicon, to increase its conductivity.

Phosphorus atom is use to make n-type semiconductor.
It containing more electrons on it outer most orbit than silicon.
These extra electrons are free to move around.

boron atom is use to make p-type semiconductor.
It contain less electrons on it outer most orbit than silicon.
These create holes are free to move around.

These positive and negative charges are mobile, they can carry electrical current.
Only about one atom in millions needs to be an impurity.

In an n-type semiconductor, the majority carriers are negative charge carriers or electrons.
In a p-type semiconductor, majority carriers are holes or positive charges.

The electron diffuse from n side to p side, and holes diffuse from p side to n side through the junction. This create depletion zone on the junction it acts as barrier.

And creates positive ion on n side, and negative ion on p side.

When the diode is forward biased, due to the negative terminal on the n-side, electrons from the n-side are pushed towards the p-region.
Similarly due to positive voltage on the p-side of the diode, Holes from the p-region are pushed towards n-side.

Due to this the charges on both the side get neutralize.
Hence width of the depletion region starts reducing, due to reduction in the barrier potential.
Hence large number of electrons and holes will cross the junction, and make the current to flow from anode to cathode.

When the diode is reverse biased, the hole from the p-side will get attracted towards the negative terminal of the supply, and electrons from the n-side are attracted towards the positive terminal.
Hence the depletion region increases. So, no electron flow from the junction means no current.