# Diode

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Posted (edited)

When we have in diodes electron tunelling it is said that is much easier,when the barrier is slighter and much more covering valence band on p side and conduction band on n side?How is that possible?If we have slighter barrier electron will be much less to go through that barrier?Thanks for the answer.

Edited by Justin2

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Posted (edited)
46 minutes ago, Justin2 said:

When we have in diodes electron tunelling it is said that is much easier,when the barrier is slighter and much more covering valence band on p side and conduction band on n side?How is that possible?If we have slighter barrier electron will be much less to go through that barrier?Thanks for the answer.

1) Do you know why there is a 'barrier' and and how does it work in an ordinary junction diode?

2) Have you seen the energy level model to explain tunnelling and why it occurs?

3) Have you seen or can you handle any maths to go with this?

Finally it might be better to say electron tunnelling occurs in diodes, rather than the other way round.

Edited by studiot

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1) If we just imagine like we have connect a p side with n side  that is practically impossible,but we will just imagine for understanding the physical image.So,after that there is a differrent situation in pn segment we have different quantity about electrons and gaps,the electrons are going in the p side because there are fewer and gaps in an opposite direction.So we have electrical field which  direction is from positive charge to negative charge.Between the 'borders' of p and n side there is no electric field,automatically no current,that area is called typically barrier or poor area.

2)Yes I have already seen the energy level which is showing that I have described in the first section upper,in poor area there are no charges we are  going though the zero point in our coordinate system.

3)I have seen some equations about the current densities but I don't understand the quantum theory behind that about tunelling electrons,if that barrier is smaller than it is logically to say that less electron will go through that barrier,or maybe that is connected to that statement because if the barrier is smaller there is covering between valence band on p side and conduction band on n side,so there is much more electrons,majority electrons from n side+minority electrons from p side.Is that enough good for understanding this situation?

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4 minutes ago, Justin2 said:

3)I have seen some equations about the current densities but I don't understand the quantum theory behind that about tunelling electrons,if that barrier is smaller than it is logically to say that less electron will go through that barrier,or maybe that is connected to that statement because if the barrier is smaller there is covering between valence band on p side and conduction band on n side,so there is much more electrons,majority electrons from n side+minority electrons from p side.Is that enough good for understanding this situation?

Think of the barrier as a wall. The higher the wall (energy barrier) the harder it is to jump over.

If the wall (energy barrier) is low enough then everyone (all electrons) will be able to jump over (tunnel through) it.

If the wall (energy barrier) is higher then fewer people (electrons) will be able to jump over (tunnel through) it.

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