Hall effect and semiconductors

[Ezio3.1415]

I had a problem understanding the hall effect for flow of holes... I thought flowing of holes means that the electrons are flowing the opposite direction,leaving open holes and that's it... but when reading hall effect I couldn't explain the hall effect for electrons and holes... Suppose holes are flowing to the right... A magnetic field is working perpendicular to its direction... We can see where the positive charge will be forced to gather... But if I think about electrons for this case that shows electrons are also gathering up there... That means either I have some mistake here or I had some misconception about the flow of holes in semiconductors...

 

[Naty1]

I am not sure I understand your explanation...your wording...

Wikipedia expresses my understanding pretty clearly:

http://en.wikipedia.org/wiki/Hall_effect

for conductors

One very important feature of the Hall effect is that it differentiates between positive charges moving in one direction and negative charges moving in the opposite. The Hall effect offered the first real proof that electric currents in metals are carried by moving electrons, not by protons. The Hall effect also showed that in some substances (especially p-type semiconductors), it is more appropriate to think of the current as positive "holes" moving rather than negative electrons. A common source of confusion with the Hall Effect is that holes moving to the left are really electrons moving to the right, so one expects the same sign of the Hall coefficient for both electrons and holes. This confusion, however, can only be resolved by modern quantum mechanical theory of transport in solids.[4]

For semiconductors, holes and electrons typically have different concentrations [based on the doping of the semiconductor]...and also different mobility. Wikipedia has a bit on this as well...

does that clear it up for you??

 

[Ezio3.1415]

If u read the page,you will see a line that says it can't be explained without using quantum mechanical effects... And how do u think about flowing of holes?

 

[Ezio3.1415]

No one is replying... Please tell me how you think of flow of holes in semiconductors... Does flowing of holes mean that the electrons are flowing the opposite direction,leaving open holes? And thus the holes move opposite to electron's direction...

 

[PJC01]

The Hall effect is a phenomenon that occurs in conductors, semiconductors, and insulators when a magnetic field is applied perpendicular to the direction of current flow. In semiconductors, the behavior of both electrons and holes can be observed.

In a semiconductor, the flow of holes refers to the movement of positively charged "missing" electrons in the valence band. When a magnetic field is applied, the holes will experience a force perpendicular to both the direction of current flow and the direction of the magnetic field. This force causes the holes to accumulate on one side of the semiconductor, creating a potential difference between the two sides. This potential difference can be measured and is known as the Hall voltage.

Similarly, the flow of electrons in a semiconductor also experiences a force in the presence of a magnetic field. However, the direction of this force is opposite to that of the holes, causing the electrons to accumulate on the opposite side of the semiconductor. This creates a voltage difference that is opposite in direction to the Hall voltage for holes.

It is important to note that both electrons and holes contribute to the overall current flow in a semiconductor. In fact, the majority carrier (either electrons or holes) will have a larger contribution to the current than the minority carrier. In a p-type semiconductor, holes are the majority carrier and in an n-type semiconductor, electrons are the majority carrier.

Therefore, it is not accurate to say that electrons are "also gathering up" in the same location as the holes in the Hall effect. They are accumulating on opposite sides of the semiconductor due to their opposite charges and the direction of the applied magnetic field. This phenomenon is used in many applications, such as Hall effect sensors, to measure magnetic fields and current flow in semiconductors.

In conclusion, the Hall effect in semiconductors involves the movement of both electrons and holes, and their behavior can be explained by their opposite charges and the direction of the applied magnetic field. There is no misconception about the flow of holes in semiconductors, as they are a valid concept in the study of semiconductor physics.