Behaviour of intrinsic semiconductor to an electric field

[arunkumarcea]

If I have a semiconductor junction of p-i and an electric field applied to it in forward bias, will the current flow?. How is the depletion region formed in intrinsic region since there are no free carriers there.What will be the electric field distribution through the intrinsic region?

 

[cabraham]

What makes you believe there are no free carriers in intrinsic Si? Intrinsic Si has not been doped with any acceptor or donor elements, ideally it is pure Si. Electron-hole pairs are being thermally generated constantly just like with n and p type Si. The i layer has free carriers, except of course in a depletion zone. Did this help?

Claude

 

[arunkumarcea]

How can a depletion region be formed in intrinsic Si?Will they leave behind negative ions or positive ions?

 

[cabraham]

How can a depletion region be formed in intrinsic Si?Will they leave behind negative ions or positive ions?

When an intrinsic region adjoins a doped region, there can be depletion. If a slab of intrinsic is energized w/o any p-n junctions then there is no depletion.

Claude

 

[alphy]

I can provide an explanation for the behavior of intrinsic semiconductors in the presence of an electric field. In an intrinsic semiconductor, the number of electrons and holes is equal, resulting in a balance between the two charge carriers. When an electric field is applied to the semiconductor junction in forward bias, the majority carriers (either electrons or holes) will experience a force in the direction of the electric field and will start to move towards the opposite side of the junction. This movement of charge carriers will result in a flow of current through the semiconductor.

The depletion region in the intrinsic region is formed due to the diffusion of charge carriers from the p and n regions towards the junction. In an intrinsic semiconductor, there are no impurities or dopants present to create free carriers. However, there are still some thermally generated electron-hole pairs present in the intrinsic region. When an electric field is applied, these electron-hole pairs will be separated and contribute to the formation of the depletion region.

The electric field distribution through the intrinsic region will depend on the doping concentration and the applied voltage. In a highly doped semiconductor, the electric field will be mostly concentrated near the junction due to the high concentration of charge carriers. In a lightly doped semiconductor, the electric field will be more evenly distributed throughout the intrinsic region. However, in both cases, the electric field will be strongest near the junction and will decrease as we move away from it.

In summary, the behavior of intrinsic semiconductors to an electric field is characterized by the movement of charge carriers and the formation of a depletion region. The electric field distribution through the intrinsic region will depend on the doping concentration and applied voltage.