Zener Tunneling Phenomena: Local or Non-Local Carriers?

[veejay]

in zener tunneling phenomena, are the carriers locally generated or non-locally generated?
i.e, should we assume the process as though it were generation of holes in the valence band and electrons in the conduction band?
i hope someone could shed some physics on this concept.
thanks.

 

[Gokul43201]

Actually, it's almost the other way round. Look at a tunnel-diode at small bias: The electrons from the conduction band of the n-type region tunnel across the junction, into the empty states in the valence band of the p-type region (remember, in a tunnel-diode, the Fermi energy does not lie within the band-gap).

 

[charng]

The answer to whether the carriers in zener tunneling phenomena are locally or non-locally generated is not a straightforward one. It depends on the specific conditions and materials involved in the process.

In general, zener tunneling refers to the quantum mechanical phenomenon where electrons can tunnel through a potential barrier, even if they do not have enough energy to overcome it. This can occur in materials with a high electric field, such as semiconductors, and can result in the generation of additional carriers (holes or electrons) on the other side of the barrier.

In some cases, these additional carriers can be locally generated within the material, meaning they are created from within the same region where the tunneling occurs. This can happen when the material has impurities or defects that act as sources of carriers.

However, in other cases, the carriers may be non-locally generated, meaning they are created outside of the region where the tunneling occurs. This can happen when the material has a heterojunction, where two different semiconductor materials are joined together, and the carriers are generated in one material and then tunnel through the junction into the other material.

In terms of the analogy of holes in the valence band and electrons in the conduction band, it is important to note that zener tunneling can occur in both types of materials. In a semiconductor, the valence band is typically filled with electrons and the conduction band is typically empty. However, in a heterojunction, the band structure can be different, and the carriers may be generated in either the valence or conduction band.

In summary, the process of zener tunneling can involve both locally and non-locally generated carriers, depending on the specific materials and conditions involved. It is important to consider the specific context and characteristics of the system in order to understand the mechanism of carrier generation in zener tunneling phenomena.